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path: root/drivers/pci/hotplug/pciehp_hpc.c (follow)
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* PCI: Refactor pcie_update_link_speed()Ilpo Järvinen2024-11-111-1/+1
| | | | | | | | | | | | | | | pcie_update_link_speed() is passed the Link Status register but not all callers have that value at hand nor need the value. Refactor pcie_update_link_speed() to include reading the Link Status register and create __pcie_update_link_speed() which can be used by the hotplug code that has the register value at hand beforehand (and needs the value for other purposes). Link: https://lore.kernel.org/r/20241018144755.7875-5-ilpo.jarvinen@linux.intel.com Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
* PCI: pciehp: Retain Power Indicator bits for userspace indicatorsBlazej Kucman2024-08-011-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The sysfs "attention" file normally controls the Slot Control Attention Indicator with 0 (off), 1 (on), 2 (blink) settings. 576243b3f9ea ("PCI: pciehp: Allow exclusive userspace control of indicators") added pciehp_set_raw_indicator_status() to allow userspace to directly control all four bits in both the Attention Indicator and the Power Indicator fields via the "attention" file. This is used on Intel VMD bridges so utilities like "ledmon" can use sysfs "attention" to control up to 16 indicators for NVMe device RAID status. abaaac4845a0 ("PCI: hotplug: Use FIELD_GET/PREP()") broke this by masking the sysfs data with PCI_EXP_SLTCTL_AIC, which discards the upper two bits intended for the Power Indicator Control field (PCI_EXP_SLTCTL_PIC). For NVMe devices behind an Intel VMD, ledmon settings that use the PCI_EXP_SLTCTL_PIC bits, i.e., ATTENTION_REBUILD (0x5), ATTENTION_LOCATE (0x7), ATTENTION_FAILURE (0xD), ATTENTION_OFF (0xF), no longer worked correctly. Mask with PCI_EXP_SLTCTL_AIC | PCI_EXP_SLTCTL_PIC to retain both the Attention Indicator and the Power Indicator bits. Fixes: abaaac4845a0 ("PCI: hotplug: Use FIELD_GET/PREP()") Link: https://lore.kernel.org/r/20240722141440.7210-1-blazej.kucman@intel.com Signed-off-by: Blazej Kucman <blazej.kucman@intel.com> [bhelgaas: commit log] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: stable@vger.kernel.org # v6.7+
* PCI: pciehp: Detect device replacement during system sleepLukas Wunner2024-05-301-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ricky reports that replacing a device in a hotplug slot during ACPI sleep state S3 does not cause re-enumeration on resume, as one would expect. Instead, the new device is treated as if it was the old one. There is no bulletproof way to detect device replacement, but as a heuristic, check whether the device identity in config space matches cached data in struct pci_dev (Vendor ID, Device ID, Class Code, Revision ID, Subsystem Vendor ID, Subsystem ID). Additionally, cache and compare the Device Serial Number (PCIe r6.2 sec 7.9.3). If a mismatch is detected, mark the old device disconnected (to prevent its driver from accessing the new device) and synthesize a Presence Detect Changed event. The device identity in config space which is compared here is the same as the one included in the signed Subject Alternative Name per PCIe r6.1 sec 6.31.3. Thus, the present commit prevents attacks where a valid device is replaced with a malicious device during system sleep and the valid device's driver obliviously accesses the malicious device. This is about as much as can be done at the PCI layer. Drivers may have additional ways to identify devices (such as reading a WWID from some register) and may trigger re-enumeration when detecting an identity change on resume. Link: https://lore.kernel.org/r/a1afaa12f341d146ecbea27c1743661c71683833.1716992815.git.lukas@wunner.de Reported-by: Ricky Wu <ricky_wu@realtek.com> Closes: https://lore.kernel.org/r/a608b5930d0a48f092f717c0e137454b@realtek.com Tested-by: Ricky Wu <ricky_wu@realtek.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
* PCI: hotplug: Use FIELD_GET/PREP()Ilpo Järvinen2023-10-241-2/+3
| | | | | | | | | Instead of handcrafted shifts to handle register fields, use FIELD_GET/FIELD_PREP(). Link: https://lore.kernel.org/r/20231018113254.17616-4-ilpo.jarvinen@linux.intel.com Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
* PCI: pciehp: Use RMW accessors for changing LNKCTLIlpo Järvinen2023-08-101-9/+3
| | | | | | | | | | | | As hotplug is not the only driver touching LNKCTL, use the RMW capability accessor which handles concurrent changes correctly. Suggested-by: Lukas Wunner <lukas@wunner.de> Fixes: 7f822999e12a ("PCI: pciehp: Add Disable/enable link functions") Link: https://lore.kernel.org/r/20230717120503.15276-4-ilpo.jarvinen@linux.intel.com Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: "Rafael J. Wysocki" <rafael@kernel.org>
* Merge branch 'pci/hotplug'Bjorn Helgaas2023-06-261-4/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | - Simplify Attention Button logging (Bjorn Helgaas) - Cancel bringup sequence if card is not present, to keep from blinking Power Indicator indefinitely (Rongguang Wei) - Reassign bridge resources if necessary for ACPI hotplug (Igor Mammedov) * pci/hotplug: PCI: acpiphp: Reassign resources on bridge if necessary PCI: pciehp: Cancel bringup sequence if card is not present PCI: pciehp: Simplify Attention Button logging
| * PCI: pciehp: Simplify Attention Button loggingBjorn Helgaas2023-05-241-4/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, pressing the Attention Button always logged two lines, the first from pciehp_ist() and the second from pciehp_handle_button_press(): Attention button pressed Powering on due to button press Since pciehp_handle_button_press() always logs the more detailed message, remove the generic "Attention button pressed" message. Reword the pciehp_handle_button_press() to be of the form: Button press: will power on in 5 sec Button press: will power off in 5 sec Button press: canceling request to power on Button press: canceling request to power off Button press: ignoring invalid state %#x Link: https://lore.kernel.org/r/20230522214051.619337-1-helgaas@kernel.org Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Lukas Wunner <lukas@wunner.de>
* | PCI: pciehp: Rely on dev->link_active_reportingMaciej W. Rozycki2023-06-151-5/+2
|/ | | | | | | | | | Use dev->link_active_reporting to determine whether Data Link Layer Link Active Reporting is available rather than re-retrieving the capability. Link: https://lore.kernel.org/r/alpine.DEB.2.21.2305310028150.59226@angie.orcam.me.uk Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Lukas Wunner <lukas@wunner.de>
* PCI: pciehp: Add Qualcomm quirk for Command Completed erratumManivannan Sadhasivam2023-02-141-0/+2
| | | | | | | | | | | | | | | | | | | The Qualcomm PCI bridge device (Device ID 0x010e) found in chipsets such as SC8280XP used in Lenovo Thinkpad X13s, does not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. This results in timeouts like below during boot and resume from suspend: pcieport 0002:00:00.0: pciehp: Timeout on hotplug command 0x03c0 (issued 2020 msec ago) ... pcieport 0002:00:00.0: pciehp: Timeout on hotplug command 0x13f1 (issued 107724 msec ago) Add the device to the Command Completed quirk to mark commands "completed" immediately unless they change the "Control" bits. Link: https://lore.kernel.org/r/20230213144922.89982-1-manivannan.sadhasivam@linaro.org Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
* PCI: pciehp: Enable Command Completed Interrupt only if supportedPali Rohár2022-12-071-1/+3
| | | | | | | | | | | | | | | | | | | The No Command Completed Support bit in the Slot Capabilities register indicates whether Command Completed Interrupt Enable is unsupported. We already check whether No Command Completed Support bit is set in pcie_wait_cmd(), and do not wait in this case. Don't enable this Command Completed Interrupt at all if NCCS is set, so that when users dump configuration space from userspace, the dump does not confuse them by saying that Command Completed Interrupt is not supported, but it is enabled. Link: https://lore.kernel.org/r/20220927141926.8895-2-kabel@kernel.org Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Marek Behún <kabel@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Lukas Wunner <lukas@wunner.de>
* PCI: pciehp: Add Qualcomm quirk for Command Completed erratumManivannan Sadhasivam2022-02-101-0/+2
| | | | | | | | | | | | | | | | | The Qualcomm PCI bridge device (Device ID 0x0110) found in chipsets such as SM8450 does not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. This results in timeouts like below: pcieport 0001:00:00.0: pciehp: Timeout on hotplug command 0x03c0 (issued 2020 msec ago) Add the device to the Command Completed quirk to mark commands "completed" immediately unless they change the "Control" bits. Link: https://lore.kernel.org/r/20220210145003.135907-1-manivannan.sadhasivam@linaro.org Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
* PCI: pciehp: Clear cmd_busy bit in polling modeLiguang Zhang2022-02-031-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Writes to a Downstream Port's Slot Control register are PCIe hotplug "commands." If the Port supports Command Completed events, software must wait for a command to complete before writing to Slot Control again. pcie_do_write_cmd() sets ctrl->cmd_busy when it writes to Slot Control. If software notification is enabled, i.e., PCI_EXP_SLTCTL_HPIE and PCI_EXP_SLTCTL_CCIE are set, ctrl->cmd_busy is cleared by pciehp_isr(). But when software notification is disabled, as it is when pcie_init() powers off an empty slot, pcie_wait_cmd() uses pcie_poll_cmd() to poll for command completion, and it neglects to clear ctrl->cmd_busy, which leads to spurious timeouts: pcieport 0000:00:03.0: pciehp: Timeout on hotplug command 0x01c0 (issued 2264 msec ago) pcieport 0000:00:03.0: pciehp: Timeout on hotplug command 0x05c0 (issued 2288 msec ago) Clear ctrl->cmd_busy in pcie_poll_cmd() when it detects a Command Completed event (PCI_EXP_SLTSTA_CC). [bhelgaas: commit log] Fixes: a5dd4b4b0570 ("PCI: pciehp: Wait for hotplug command completion where necessary") Link: https://lore.kernel.org/r/20211111054258.7309-1-zhangliguang@linux.alibaba.com Link: https://bugzilla.kernel.org/show_bug.cgi?id=215143 Link: https://lore.kernel.org/r/20211126173309.GA12255@wunner.de Signed-off-by: Liguang Zhang <zhangliguang@linux.alibaba.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Lukas Wunner <lukas@wunner.de> Cc: stable@vger.kernel.org # v4.19+
* Merge branch 'pci/errors'Bjorn Helgaas2022-01-131-5/+5
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Add PCI_ERROR_RESPONSE and related definitions for signaling and checking for transaction errors on PCI (Naveen Naidu) - Fabricate PCI_ERROR_RESPONSE data (~0) in config read wrappers, instead of in host controller drivers, when transactions fail on PCI (Naveen Naidu) - Use PCI_POSSIBLE_ERROR() to check for possible failure of config reads (Naveen Naidu) * pci/errors: PCI: xgene: Use PCI_ERROR_RESPONSE to identify config read errors PCI: hv: Use PCI_ERROR_RESPONSE to identify config read errors PCI: keystone: Use PCI_ERROR_RESPONSE to identify config read errors PCI: Use PCI_ERROR_RESPONSE to identify config read errors PCI: cpqphp: Use PCI_POSSIBLE_ERROR() to check config reads PCI/PME: Use PCI_POSSIBLE_ERROR() to check config reads PCI/DPC: Use PCI_POSSIBLE_ERROR() to check config reads PCI: pciehp: Use PCI_POSSIBLE_ERROR() to check config reads PCI: vmd: Use PCI_POSSIBLE_ERROR() to check config reads PCI/ERR: Use PCI_POSSIBLE_ERROR() to check config reads PCI: rockchip-host: Drop error data fabrication when config read fails PCI: rcar-host: Drop error data fabrication when config read fails PCI: altera: Drop error data fabrication when config read fails PCI: mvebu: Drop error data fabrication when config read fails PCI: aardvark: Drop error data fabrication when config read fails PCI: kirin: Drop error data fabrication when config read fails PCI: histb: Drop error data fabrication when config read fails PCI: exynos: Drop error data fabrication when config read fails PCI: mediatek: Drop error data fabrication when config read fails PCI: iproc: Drop error data fabrication when config read fails PCI: thunder: Drop error data fabrication when config read fails PCI: Drop error data fabrication when config read fails PCI: Use PCI_SET_ERROR_RESPONSE() for disconnected devices PCI: Set error response data when config read fails PCI: Add PCI_ERROR_RESPONSE and related definitions
| * PCI: pciehp: Use PCI_POSSIBLE_ERROR() to check config readsNaveen Naidu2021-11-181-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When config pci_ops.read() can detect failed PCI transactions, the data returned to the CPU is PCI_ERROR_RESPONSE (~0 or 0xffffffff). Obviously a successful PCI config read may *also* return that data if a config register happens to contain ~0, so it doesn't definitively indicate an error unless we know the register cannot contain ~0. Use PCI_POSSIBLE_ERROR() to check the response we get when we read data from hardware. This unifies PCI error response checking and makes error checks consistent and easier to find. Compile tested only. Link: https://lore.kernel.org/r/e185b052fbfd530df703a36dd31126cb870eed95.1637243717.git.naveennaidu479@gmail.com Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Lukas Wunner <lukas@wunner.de>
* | PCI: pciehp: Use down_read/write_nested(reset_lock) to fix lockdep errorsHans de Goede2022-01-121-3/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use down_read_nested() and down_write_nested() when taking the ctrl->reset_lock rw-sem, passing the number of PCIe hotplug controllers in the path to the PCI root bus as lock subclass parameter. This fixes the following false-positive lockdep report when unplugging a Lenovo X1C8 from a Lenovo 2nd gen TB3 dock: pcieport 0000:06:01.0: pciehp: Slot(1): Link Down pcieport 0000:06:01.0: pciehp: Slot(1): Card not present ============================================ WARNING: possible recursive locking detected 5.16.0-rc2+ #621 Not tainted -------------------------------------------- irq/124-pciehp/86 is trying to acquire lock: ffff8e5ac4299ef8 (&ctrl->reset_lock){.+.+}-{3:3}, at: pciehp_check_presence+0x23/0x80 but task is already holding lock: ffff8e5ac4298af8 (&ctrl->reset_lock){.+.+}-{3:3}, at: pciehp_ist+0xf3/0x180 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&ctrl->reset_lock); lock(&ctrl->reset_lock); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by irq/124-pciehp/86: #0: ffff8e5ac4298af8 (&ctrl->reset_lock){.+.+}-{3:3}, at: pciehp_ist+0xf3/0x180 #1: ffffffffa3b024e8 (pci_rescan_remove_lock){+.+.}-{3:3}, at: pciehp_unconfigure_device+0x31/0x110 #2: ffff8e5ac1ee2248 (&dev->mutex){....}-{3:3}, at: device_release_driver+0x1c/0x40 stack backtrace: CPU: 4 PID: 86 Comm: irq/124-pciehp Not tainted 5.16.0-rc2+ #621 Hardware name: LENOVO 20U90SIT19/20U90SIT19, BIOS N2WET30W (1.20 ) 08/26/2021 Call Trace: <TASK> dump_stack_lvl+0x59/0x73 __lock_acquire.cold+0xc5/0x2c6 lock_acquire+0xb5/0x2b0 down_read+0x3e/0x50 pciehp_check_presence+0x23/0x80 pciehp_runtime_resume+0x5c/0xa0 device_for_each_child+0x45/0x70 pcie_port_device_runtime_resume+0x20/0x30 pci_pm_runtime_resume+0xa7/0xc0 __rpm_callback+0x41/0x110 rpm_callback+0x59/0x70 rpm_resume+0x512/0x7b0 __pm_runtime_resume+0x4a/0x90 __device_release_driver+0x28/0x240 device_release_driver+0x26/0x40 pci_stop_bus_device+0x68/0x90 pci_stop_bus_device+0x2c/0x90 pci_stop_and_remove_bus_device+0xe/0x20 pciehp_unconfigure_device+0x6c/0x110 pciehp_disable_slot+0x5b/0xe0 pciehp_handle_presence_or_link_change+0xc3/0x2f0 pciehp_ist+0x179/0x180 This lockdep warning is triggered because with Thunderbolt, hotplug ports are nested. When removing multiple devices in a daisy-chain, each hotplug port's reset_lock may be acquired recursively. It's never the same lock, so the lockdep splat is a false positive. Because locks at the same hierarchy level are never acquired recursively, a per-level lockdep class is sufficient to fix the lockdep warning. The choice to use one lockdep subclass per pcie-hotplug controller in the path to the root-bus was made to conserve class keys because their number is limited and the complexity grows quadratically with number of keys according to Documentation/locking/lockdep-design.rst. Link: https://lore.kernel.org/linux-pci/20190402021933.GA2966@mit.edu/ Link: https://lore.kernel.org/linux-pci/de684a28-9038-8fc6-27ca-3f6f2f6400d7@redhat.com/ Link: https://lore.kernel.org/r/20211217141709.379663-1-hdegoede@redhat.com Link: https://bugzilla.kernel.org/show_bug.cgi?id=208855 Reported-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Lukas Wunner <lukas@wunner.de> Cc: stable@vger.kernel.org
* | PCI: pciehp: Fix infinite loop in IRQ handler upon power faultLukas Wunner2021-11-191-3/+4
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The Power Fault Detected bit in the Slot Status register differs from all other hotplug events in that it is sticky: It can only be cleared after turning off slot power. Per PCIe r5.0, sec. 6.7.1.8: If a power controller detects a main power fault on the hot-plug slot, it must automatically set its internal main power fault latch [...]. The main power fault latch is cleared when software turns off power to the hot-plug slot. The stickiness used to cause interrupt storms and infinite loops which were fixed in 2009 by commits 5651c48cfafe ("PCI pciehp: fix power fault interrupt storm problem") and 99f0169c17f3 ("PCI: pciehp: enable software notification on empty slots"). Unfortunately in 2020 the infinite loop issue was inadvertently reintroduced by commit 8edf5332c393 ("PCI: pciehp: Fix MSI interrupt race"): The hardirq handler pciehp_isr() clears the PFD bit until pciehp's power_fault_detected flag is set. That happens in the IRQ thread pciehp_ist(), which never learns of the event because the hardirq handler is stuck in an infinite loop. Fix by setting the power_fault_detected flag already in the hardirq handler. Link: https://bugzilla.kernel.org/show_bug.cgi?id=214989 Link: https://lore.kernel.org/linux-pci/DM8PR11MB5702255A6A92F735D90A4446868B9@DM8PR11MB5702.namprd11.prod.outlook.com Fixes: 8edf5332c393 ("PCI: pciehp: Fix MSI interrupt race") Link: https://lore.kernel.org/r/66eaeef31d4997ceea357ad93259f290ededecfd.1637187226.git.lukas@wunner.de Reported-by: Joseph Bao <joseph.bao@intel.com> Tested-by: Joseph Bao <joseph.bao@intel.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: stable@vger.kernel.org # v4.19+ Cc: Stuart Hayes <stuart.w.hayes@gmail.com>
* PCI: pciehp: Ignore Link Down/Up caused by error-induced Hot ResetLukas Wunner2021-10-151-0/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Stuart Hayes reports that an error handled by DPC at a Root Port results in pciehp gratuitously bringing down a subordinate hotplug port: RP -- UP -- DP -- UP -- DP (hotplug) -- EP pciehp brings the slot down because the Link to the Endpoint goes down. That is caused by a Hot Reset being propagated as a result of DPC. Per PCIe Base Spec 5.0, section 6.6.1 "Conventional Reset": For a Switch, the following must cause a hot reset to be sent on all Downstream Ports: [...] * The Data Link Layer of the Upstream Port reporting DL_Down status. In Switches that support Link speeds greater than 5.0 GT/s, the Upstream Port must direct the LTSSM of each Downstream Port to the Hot Reset state, but not hold the LTSSMs in that state. This permits each Downstream Port to begin Link training immediately after its hot reset completes. This behavior is recommended for all Switches. * Receiving a hot reset on the Upstream Port. Once DPC recovers, pcie_do_recovery() walks down the hierarchy and invokes pcie_portdrv_slot_reset() to restore each port's config space. At that point, a hotplug interrupt is signaled per PCIe Base Spec r5.0, section 6.7.3.4 "Software Notification of Hot-Plug Events": If the Port is enabled for edge-triggered interrupt signaling using MSI or MSI-X, an interrupt message must be sent every time the logical AND of the following conditions transitions from FALSE to TRUE: [...] * The Hot-Plug Interrupt Enable bit in the Slot Control register is set to 1b. * At least one hot-plug event status bit in the Slot Status register and its associated enable bit in the Slot Control register are both set to 1b. Prevent pciehp from gratuitously bringing down the slot by clearing the error-induced Data Link Layer State Changed event before restoring config space. Afterwards, check whether the link has unexpectedly failed to retrain and synthesize a DLLSC event if so. Allow each pcie_port_service_driver (one of them being pciehp) to define a slot_reset callback and re-use the existing pm_iter() function to iterate over the callbacks. Thereby, the Endpoint driver remains bound throughout error recovery and may restore the device to working state. Surprise removal during error recovery is detected through a Presence Detect Changed event. The hotplug port is expected to not signal that event as a result of a Hot Reset. The issue isn't DPC-specific, it also occurs when an error is handled by AER through aer_root_reset(). So while the issue was noticed only now, it's been around since 2006 when AER support was first introduced. [bhelgaas: drop PCI_ERROR_RECOVERY Kconfig, split pm_iter() rename to preparatory patch] Link: https://lore.kernel.org/linux-pci/08c046b0-c9f2-3489-eeef-7e7aca435bb9@gmail.com/ Fixes: 6c2b374d7485 ("PCI-Express AER implemetation: AER core and aerdriver") Link: https://lore.kernel.org/r/251f4edcc04c14f873ff1c967bc686169cd07d2d.1627638184.git.lukas@wunner.de Reported-by: Stuart Hayes <stuart.w.hayes@gmail.com> Tested-by: Stuart Hayes <stuart.w.hayes@gmail.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: stable@vger.kernel.org # v2.6.19+: ba952824e6c1: PCI/portdrv: Report reset for frozen channel Cc: Keith Busch <kbusch@kernel.org>
* PCI: Change the type of probe argument in reset functionsAmey Narkhede2021-08-191-1/+1
| | | | | | | | | | Change the type of probe argument in functions which implement reset methods from int to bool to make the context and intent clear. Suggested-by: Alex Williamson <alex.williamson@redhat.com> Link: https://lore.kernel.org/r/20210817180500.1253-10-ameynarkhede03@gmail.com Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
* PCI: pciehp: Ignore Link Down/Up caused by DPCLukas Wunner2021-06-171-0/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Downstream Port Containment (PCIe r5.0, sec. 6.2.10) disables the link upon an error and attempts to re-enable it when instructed by the DPC driver. A slot which is both DPC- and hotplug-capable is currently powered off by pciehp once DPC is triggered (due to the link change) and powered back up on successful recovery. That's undesirable, the slot should remain powered so the hotplugged device remains bound to its driver. DPC notifies the driver of the error and of successful recovery in pcie_do_recovery() and the driver may then restore the device to working state. Moreover, Sinan points out that turning off slot power by pciehp may foil recovery by DPC: Power off/on is a cold reset concurrently to DPC's warm reset. Sathyanarayanan reports extended delays or failure in link retraining by DPC if pciehp brings down the slot. Fix by detecting whether a Link Down event is caused by DPC and awaiting recovery if so. On successful recovery, ignore both the Link Down and the subsequent Link Up event. Afterwards, check whether the link is down to detect surprise-removal or another DPC event immediately after DPC recovery. Ensure that the corresponding DLLSC event is not ignored by synthesizing it and invoking irq_wake_thread() to trigger a re-run of pciehp_ist(). The IRQ threads of the hotplug and DPC drivers, pciehp_ist() and dpc_handler(), race against each other. If pciehp is faster than DPC, it will wait until DPC recovery completes. Recovery consists of two steps: The first step (waiting for link disablement) is recognizable by pciehp through a set DPC Trigger Status bit. The second step (waiting for link retraining) is recognizable through a newly introduced PCI_DPC_RECOVERING flag. If DPC is faster than pciehp, neither of the two flags will be set and pciehp may glean the recovery status from the new PCI_DPC_RECOVERED flag. The flag is zero if DPC didn't occur at all, hence DLLSC events are not ignored by default. pciehp waits up to 4 seconds before assuming that DPC recovery failed and bringing down the slot. This timeout is not taken from the spec (it doesn't mandate one) but based on a report from Yicong Yang that DPC may take a bit more than 3 seconds on HiSilicon's Kunpeng platform. The timeout is necessary because the DPC Trigger Status bit may never clear: On Root Ports which support RP Extensions for DPC, the DPC driver polls the DPC RP Busy bit for up to 1 second before giving up on DPC recovery. Without the timeout, pciehp would then wait indefinitely for DPC to complete. This commit draws inspiration from previous attempts to synchronize DPC with pciehp: By Sinan Kaya, August 2018: https://lore.kernel.org/linux-pci/20180818065126.77912-1-okaya@kernel.org/ By Ethan Zhao, October 2020: https://lore.kernel.org/linux-pci/20201007113158.48933-1-haifeng.zhao@intel.com/ By Kuppuswamy Sathyanarayanan, March 2021: https://lore.kernel.org/linux-pci/59cb30f5e5ac6d65427ceaadf1012b2ba8dbf66c.1615606143.git.sathyanarayanan.kuppuswamy@linux.intel.com/ Link: https://lore.kernel.org/r/0be565d97438fe2a6d57354b3aa4e8626952a00b.1619857124.git.lukas@wunner.de Reported-by: Sinan Kaya <okaya@kernel.org> Reported-by: Ethan Zhao <haifeng.zhao@intel.com> Reported-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Tested-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Tested-by: Yicong Yang <yangyicong@hisilicon.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Keith Busch <kbusch@kernel.org>
* PCI: pciehp: Reduce noisiness on hot removalLukas Wunner2020-09-171-6/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a PCIe card is hot-removed, the Presence Detect State and Data Link Layer Link Active bits often do not clear simultaneously. I've seen delays of up to 244 msec between the two events with Thunderbolt. After pciehp has brought down the slot in response to the first event, the other bit may still be set. It's not discernible whether it's set because a new card is already in the slot or if it will soon clear. So pciehp tries to bring up the slot and in the latter case fails with a bunch of messages, some of them at KERN_ERR severity. If the slot is no longer occupied, the messages are false positives and annoy users. Stuart Hayes reports the following splat on hot removal: KERN_INFO pcieport 0000:3c:06.0: pciehp: Slot(180): Link Up KERN_INFO pcieport 0000:3c:06.0: pciehp: Timeout waiting for Presence Detect KERN_ERR pcieport 0000:3c:06.0: pciehp: link training error: status 0x0001 KERN_ERR pcieport 0000:3c:06.0: pciehp: Failed to check link status Dongdong Liu complains about a similar splat: KERN_INFO pciehp 0000:80:10.0:pcie004: Slot(36): Link Down KERN_INFO iommu: Removing device 0000:87:00.0 from group 12 KERN_INFO pciehp 0000:80:10.0:pcie004: Slot(36): Card present KERN_INFO pcieport 0000:80:10.0: Data Link Layer Link Active not set in 1000 msec KERN_ERR pciehp 0000:80:10.0:pcie004: Failed to check link status Users are particularly irritated to see a bringup attempt even though the slot was explicitly brought down via sysfs. In a perfect world, we could avoid this by setting Link Disable on slot bringdown and re-enabling it upon a Presence Detect State change. In reality however, there are broken hotplug ports which hardwire Presence Detect to zero, see 80696f991424 ("PCI: pciehp: Tolerate Presence Detect hardwired to zero"). Conversely, PCIe r1.0 hotplug ports hardwire Link Active to zero because Link Active Reporting wasn't specified before PCIe r1.1. On unplug, some ports first clear Presence then Link (see Stuart Hayes' splat) whereas others use the inverse order (see Dongdong Liu's splat). To top it off, there are hotplug ports which flap the Presence and Link bits on slot bringup, see 6c35a1ac3da6 ("PCI: pciehp: Tolerate initially unstable link"). pciehp is designed to work with all of these variants. Surplus attempts at slot bringup are a lesser evil than not being able to bring up slots at all. Although we could try to perfect the behavior for specific hotplug controllers, we'd risk breaking others or increasing code complexity. But we can certainly minimize annoyance by emitting only a single message with KERN_INFO severity if bringup is unsuccessful: * Drop the "Timeout waiting for Presence Detect" message in pcie_wait_for_presence(). The sole caller of that function, pciehp_check_link_status(), ignores the timeout and carries on. It emits error messages of its own and I don't think this particular message adds much value. * There's a single error condition in pciehp_check_link_status() which does not emit a message. Adding one allows dropping the "Failed to check link status" message emitted by board_added() if pciehp_check_link_status() returns a non-zero integer. * Tone down all messages in pciehp_check_link_status() to KERN_INFO severity and rephrase them to look as innocuous as possible. To this end, move the message emitted by pcie_wait_for_link_delay() to its callers. As a result, Stuart Hayes' splat becomes: KERN_INFO pcieport 0000:3c:06.0: pciehp: Slot(180): Link Up KERN_INFO pcieport 0000:3c:06.0: pciehp: Slot(180): Cannot train link: status 0x0001 Dongdong Liu's splat becomes: KERN_INFO pciehp 0000:80:10.0:pcie004: Slot(36): Card present KERN_INFO pciehp 0000:80:10.0:pcie004: Slot(36): No link The messages now merely serve as information that presence or link bits were set a little longer than expected. Bringup failures which are not false positives are still reported, albeit no longer at KERN_ERR severity. Link: https://lore.kernel.org/linux-pci/20200310182100.102987-1-stuart.w.hayes@gmail.com/ Link: https://lore.kernel.org/linux-pci/1547649064-19019-1-git-send-email-liudongdong3@huawei.com/ Link: https://lore.kernel.org/r/b45e46fd8a6aa6930aaac9d7718c2e4b787a4e5e.1595935071.git.lukas@wunner.de Reported-by: Stuart Hayes <stuart.w.hayes@gmail.com> Reported-by: Dongdong Liu <liudongdong3@huawei.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
* PCI: pciehp: Fix MSI interrupt raceStuart Hayes2020-03-311-6/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Without this commit, a PCIe hotplug port can stop generating interrupts on hotplug events, so device adds and removals will not be seen: The pciehp interrupt handler pciehp_isr() reads the Slot Status register and then writes back to it to clear the bits that caused the interrupt. If a different interrupt event bit gets set between the read and the write, pciehp_isr() returns without having cleared all of the interrupt event bits. If this happens when the MSI isn't masked (which by default it isn't in handle_edge_irq(), and which it will never be when MSI per-vector masking is not supported), we won't get any more hotplug interrupts from that device. That is expected behavior, according to the PCIe Base Spec r5.0, section 6.7.3.4, "Software Notification of Hot-Plug Events". Because the Presence Detect Changed and Data Link Layer State Changed event bits can both get set at nearly the same time when a device is added or removed, this is more likely to happen than it might seem. The issue was found (and can be reproduced rather easily) by connecting and disconnecting an NVMe storage device on at least one system model where the NVMe devices were being connected to an AMD PCIe port (PCI device 0x1022/0x1483). Fix the issue by modifying pciehp_isr() to loop back and re-read the Slot Status register immediately after writing to it, until it sees that all of the event status bits have been cleared. [lukas: drop loop count limitation, write "events" instead of "status", don't loop back in INTx and poll modes, tweak code comment & commit msg] Link: https://lore.kernel.org/r/78b4ced5072bfe6e369d20e8b47c279b8c7af12e.1582121613.git.lukas@wunner.de Tested-by: Stuart Hayes <stuart.w.hayes@gmail.com> Signed-off-by: Stuart Hayes <stuart.w.hayes@gmail.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Joerg Roedel <jroedel@suse.de>
* PCI: pciehp: Fix indefinite wait on sysfs requestsLukas Wunner2020-03-311-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | David Hoyer reports that powering pciehp slots up or down via sysfs may hang: The call to wait_event() in pciehp_sysfs_enable_slot() and _disable_slot() does not return because ctrl->ist_running remains true. This flag, which was introduced by commit 157c1062fcd8 ("PCI: pciehp: Avoid returning prematurely from sysfs requests"), signifies that the IRQ thread pciehp_ist() is running. It is set to true at the top of pciehp_ist() and reset to false at the end. However there are two additional return statements in pciehp_ist() before which the commit neglected to reset the flag to false and wake up waiters for the flag. That omission opens up the following race when powering up the slot: * pciehp_ist() runs because a PCI_EXP_SLTSTA_PDC event was requested by pciehp_sysfs_enable_slot() * pciehp_ist() turns on slot power via the following call stack: pciehp_handle_presence_or_link_change() -> pciehp_enable_slot() -> __pciehp_enable_slot() -> board_added() -> pciehp_power_on_slot() * after slot power is turned on, the link comes up, resulting in a PCI_EXP_SLTSTA_DLLSC event * the IRQ handler pciehp_isr() stores the event in ctrl->pending_events and returns IRQ_WAKE_THREAD * the IRQ thread is already woken (it's bringing up the slot), but the genirq code remembers to re-run the IRQ thread after it has finished (such that it can deal with the new event) by setting IRQTF_RUNTHREAD via __handle_irq_event_percpu() -> __irq_wake_thread() * the IRQ thread removes PCI_EXP_SLTSTA_DLLSC from ctrl->pending_events via board_added() -> pciehp_check_link_status() in order to deal with presence and link flaps per commit 6c35a1ac3da6 ("PCI: pciehp: Tolerate initially unstable link") * after pciehp_ist() has successfully brought up the slot, it resets ctrl->ist_running to false and wakes up the sysfs requester * the genirq code re-runs pciehp_ist(), which sets ctrl->ist_running to true but then returns with IRQ_NONE because ctrl->pending_events is empty * pciehp_sysfs_enable_slot() is finally woken but notices that ctrl->ist_running is true, hence continues waiting The only way to get the hung task going again is to trigger a hotplug event which brings down the slot, e.g. by yanking out the card. The same race exists when powering down the slot because remove_board() likewise clears link or presence changes in ctrl->pending_events per commit 3943af9d01e9 ("PCI: pciehp: Ignore Link State Changes after powering off a slot") and thereby may cause a re-run of pciehp_ist() which returns with IRQ_NONE without resetting ctrl->ist_running to false. Fix by adding a goto label before the teardown steps at the end of pciehp_ist() and jumping to that label from the two return statements which currently neglect to reset the ctrl->ist_running flag. Fixes: 157c1062fcd8 ("PCI: pciehp: Avoid returning prematurely from sysfs requests") Link: https://lore.kernel.org/r/cca1effa488065cb055120aa01b65719094bdcb5.1584530321.git.lukas@wunner.de Reported-by: David Hoyer <David.Hoyer@netapp.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Keith Busch <kbusch@kernel.org> Cc: stable@vger.kernel.org # v4.19+
* PCI: pciehp: Add DMI table for in-band presence detection disabledStuart Hayes2020-02-211-0/+22
| | | | | | | | | | | | | | | | | Some systems have in-band presence detection disabled for hot-plug PCI slots but do not report this in the slot capabilities 2 (SLTCAP2) register. On these systems, presence detect can become active well after the link is reported to be active, which can cause the slots to be disabled after a device is connected. Add a DMI table to flag these systems as having in-band presence detect disabled. Link: https://lore.kernel.org/r/20191025190047.38130-4-stuart.w.hayes@gmail.com Signed-off-by: Stuart Hayes <stuart.w.hayes@gmail.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Reviewed-by: Lukas Wunner <lukas@wunner.de>
* PCI: pciehp: Wait for PDS if in-band presence is disabledAlexandru Gagniuc2020-02-211-0/+19
| | | | | | | | | | | | | | | | | | | | | When in-band presence detect is disabled, PDS may come up at any time or not at all. PDS being low may indicate that the card is still mating, and we could expect contact bounce to bring down the link as well. It is reasonable to assume that most cards will mate in a hotplug slot in about a second. Thus, when we know PDS only reflects out-of-band presence detect, it's worthwhile to wait the extra second or so to make sure the card is properly mated before loading the driver and to prevent the hotplug code from disabling a device if the presence detect change goes active after the device is enabled. Link: https://lore.kernel.org/r/20191025190047.38130-3-stuart.w.hayes@gmail.com [bhelgaas: use ctrl_info() instead of pci_info()] Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com> Signed-off-by: Stuart Hayes <stuart.w.hayes@gmail.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Reviewed-by: Lukas Wunner <lukas@wunner.de>
* PCI: pciehp: Disable in-band presence detect when possibleAlexandru Gagniuc2020-02-211-2/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The presence detect state (PDS) is normally a logical OR of in-band and out-of-band (OOB) presence detect. As of PCIe 4.0, there is the option to disable in-band presence so that the PDS bit always reflects the state of the out-of-band presence. The recommendation of the PCIe spec is to disable in-band presence whenever supported (PCIe r5.0, appendix I implementation note): Due to architectural issues, the in-band (Physical-Layer-based) portion of the PD mechanism is deprecated for use with async hot-plug. One issue is that in-band PD as architected does not detect adapter removal during certain LTSSM states, notably the L1 and Disabled States. Another issue is that when both in-band and OOB PD are being used together, the Presence Detect State bit and its associated interrupt mechanism always reflect the logical OR of the inband and OOB PD states, and with some hot-plug hardware configurations, it is important for software to detect and respond to in-band and OOB PD events independently. If OOB PD is being used and the associated DSP supports In-Band PD Disable, it is recommended that the In-Band PD Disable bit be Set, and the Presence Detect State bit and its associated interrupt mechanism be used exclusively for OOB PD. As a substitute for in-band PD with async hot-plug, the reference model uses either the DPC or the DLL Link Active mechanism. Link: https://lore.kernel.org/r/20191025190047.38130-2-stuart.w.hayes@gmail.com [bhelgaas: move PCI_EXP_SLTCAP2 read earlier & print PCI_EXP_SLTCAP2_IBPD value (suggested by Lukas)] Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Reviewed-by: Lukas Wunner <lukas@wunner.de>
* PCI: pciehp: Prevent deadlock on disconnectMika Westerberg2019-11-131-11/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This addresses deadlocks in these common cases in hierarchies containing two switches: - All involved ports are runtime suspended and they are unplugged. This can happen easily if the drivers involved automatically enable runtime PM (xHCI for example does that). - System is suspended (e.g., closing the lid on a laptop) with a dock + something else connected, and the dock is unplugged while suspended. These cases lead to the following deadlock: INFO: task irq/126-pciehp:198 blocked for more than 120 seconds. irq/126-pciehp D 0 198 2 0x80000000 Call Trace: schedule+0x2c/0x80 schedule_timeout+0x246/0x350 wait_for_completion+0xb7/0x140 kthread_stop+0x49/0x110 free_irq+0x32/0x70 pcie_shutdown_notification+0x2f/0x50 pciehp_remove+0x27/0x50 pcie_port_remove_service+0x36/0x50 device_release_driver+0x12/0x20 bus_remove_device+0xec/0x160 device_del+0x13b/0x350 device_unregister+0x1a/0x60 remove_iter+0x1e/0x30 device_for_each_child+0x56/0x90 pcie_port_device_remove+0x22/0x40 pcie_portdrv_remove+0x20/0x60 pci_device_remove+0x3e/0xc0 device_release_driver_internal+0x18c/0x250 device_release_driver+0x12/0x20 pci_stop_bus_device+0x6f/0x90 pci_stop_bus_device+0x31/0x90 pci_stop_and_remove_bus_device+0x12/0x20 pciehp_unconfigure_device+0x88/0x140 pciehp_disable_slot+0x6a/0x110 pciehp_handle_presence_or_link_change+0x263/0x400 pciehp_ist+0x1c9/0x1d0 irq_thread_fn+0x24/0x60 irq_thread+0xeb/0x190 kthread+0x120/0x140 INFO: task irq/190-pciehp:2288 blocked for more than 120 seconds. irq/190-pciehp D 0 2288 2 0x80000000 Call Trace: __schedule+0x2a2/0x880 schedule+0x2c/0x80 schedule_preempt_disabled+0xe/0x10 mutex_lock+0x2c/0x30 pci_lock_rescan_remove+0x15/0x20 pciehp_unconfigure_device+0x4d/0x140 pciehp_disable_slot+0x6a/0x110 pciehp_handle_presence_or_link_change+0x263/0x400 pciehp_ist+0x1c9/0x1d0 irq_thread_fn+0x24/0x60 irq_thread+0xeb/0x190 kthread+0x120/0x140 What happens here is that the whole hierarchy is runtime resumed and the parent PCIe downstream port, which got the hot-remove event, starts removing devices below it, taking pci_lock_rescan_remove() lock. When the child PCIe port is runtime resumed it calls pciehp_check_presence() which ends up calling pciehp_card_present() and pciehp_check_link_active(). Both of these use pcie_capability_read_word(), which notices that the underlying device is already gone and returns PCIBIOS_DEVICE_NOT_FOUND with the capability value set to 0. When pciehp gets this value it thinks that its child device is also hot-removed and schedules its IRQ thread to handle the event. The deadlock happens when the child's IRQ thread runs and tries to acquire pci_lock_rescan_remove() which is already taken by the parent and the parent waits for the child's IRQ thread to finish. Prevent this from happening by checking the return value of pcie_capability_read_word() and if it is PCIBIOS_DEVICE_NOT_FOUND stop performing any hot-removal activities. [bhelgaas: add common scenarios to commit log] Link: https://lore.kernel.org/r/20191029170022.57528-2-mika.westerberg@linux.intel.com Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
* PCI: pciehp: Refactor infinite loop in pcie_poll_cmd()Andy Shevchenko2019-11-121-4/+2
| | | | | | | | | | | | | | | | Infinite timeout loops are hard to read. Refactor it to plausible 'do {} while ()'. Note, the supplied timeout can't be negative for current use, though if it's not dividable to 10, we may go below 0, that's why type of the parameter is int. And thus, we may move the check to the loop condition. No functional change intended. Link: https://lore.kernel.org/r/20191108111855.85866-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Andrew Murray <andrew.murray@arm.com>
* PCI: pciehp: Avoid returning prematurely from sysfs requestsLukas Wunner2019-10-041-0/+2
| | | | | | | | | | | | | | | | | | | | | | | A sysfs request to enable or disable a PCIe hotplug slot should not return before it has been carried out. That is sought to be achieved by waiting until the controller's "pending_events" have been cleared. However the IRQ thread pciehp_ist() clears the "pending_events" before it acts on them. If pciehp_sysfs_enable_slot() / _disable_slot() happen to check the "pending_events" after they have been cleared but while pciehp_ist() is still running, the functions may return prematurely with an incorrect return value. Fix by introducing an "ist_running" flag which must be false before a sysfs request is allowed to return. Fixes: 32a8cef274fe ("PCI: pciehp: Enable/disable exclusively from IRQ thread") Link: https://lore.kernel.org/linux-pci/1562226638-54134-1-git-send-email-wangxiongfeng2@huawei.com Link: https://lore.kernel.org/r/4174210466e27eb7e2243dd1d801d5f75baaffd8.1565345211.git.lukas@wunner.de Reported-and-tested-by: Xiongfeng Wang <wangxiongfeng2@huawei.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: stable@vger.kernel.org # v4.19+
* PCI: pciehp: Remove pciehp_green_led_{on,off,blink}()Denis Efremov2019-09-051-36/+0
| | | | | | | | | | | | Remove pciehp_green_led_{on,off,blink}() and use pciehp_set_indicators() instead, since the code is mostly the same. [bhelgaas: drop set_power_indicator() wrapper to reduce the number of interfaces] Link: https://lore.kernel.org/r/20190903111021.1559-5-efremov@linux.com Signed-off-by: Denis Efremov <efremov@linux.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
* PCI: pciehp: Remove pciehp_set_attention_status()Denis Efremov2019-09-051-25/+0
| | | | | | | | | | Remove pciehp_set_attention_status() and use pciehp_set_indicators() instead, since the code is mostly the same. Link: https://lore.kernel.org/r/20190903111021.1559-4-efremov@linux.com Signed-off-by: Denis Efremov <efremov@linux.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
* PCI: pciehp: Combine adjacent indicator updatesDenis Efremov2019-09-051-2/+2
| | | | | | | | | | | | Combine adjacent updates of power and attention indicators into a single pciehp_set_indicators() call. This sends one command to the hotplug controller instead of two. Link: https://lore.kernel.org/r/20190903111021.1559-3-efremov@linux.com Signed-off-by: Denis Efremov <efremov@linux.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> Reviewed-by: Lukas Wunner <lukas@wunner.de>
* PCI: pciehp: Add pciehp_set_indicators() to set both indicatorsDenis Efremov2019-09-051-0/+36
| | | | | | | | | | | | | | | | | | | Add pciehp_set_indicators() to set power and attention indicators with a single register write. This is a minor optimization because we frequently set both indicators and this can do it with a single command. It also reduces the number of interfaces related to the indicators and makes them more discoverable because callers use the PCI_EXP_SLTCTL_ATTN_IND_* and PCI_EXP_SLTCTL_PWR_IND_* definitions directly. [bhelgaas: extend commit log, s/PCI_EXP_SLTCTL_.*_IND_NONE/INDICATOR_NOOP/ so they don't look like things defined by the spec, add function doc, mask commands to make it obvious we only send valid commands (pcie_do_write_cmd() does mask it, but requires more effort to verify)] Link: https://lore.kernel.org/r/20190903111021.1559-2-efremov@linux.com Signed-off-by: Denis Efremov <efremov@linux.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
* PCI: pciehp: Remove pointless MY_NAME definitionBjorn Helgaas2019-05-091-1/+1
| | | | | | | | | MY_NAME is only used once and offers no benefit, so remove it. Link: https://lore.kernel.org/lkml/20190509141456.223614-11-helgaas@kernel.org Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
* PCI: pciehp: Remove unused dbg/err/info/warn() wrappersFrederick Lawler2019-05-091-1/+1
| | | | | | | | | | | Replace the last uses of dbg() with the equivalent pr_debug(), then remove unused dbg(), err(), info(), and warn() wrappers. Link: https://lore.kernel.org/lkml/20190509141456.223614-9-helgaas@kernel.org Signed-off-by: Frederick Lawler <fred@fredlawl.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
* PCI: pciehp: Log messages with pci_dev, not pcie_deviceFrederick Lawler2019-05-091-0/+2
| | | | | | | | | | | | | | | | Log messages with pci_dev, not pcie_device. Factor out common message prefixes with dev_fmt(). Example output change: - pciehp 0000:00:06.0:pcie004: Slot(0) Powering on due to button press + pcieport 0000:00:06.0: pciehp: Slot(0) Powering on due to button press Link: https://lore.kernel.org/lkml/20190509141456.223614-8-helgaas@kernel.org Signed-off-by: Frederick Lawler <fred@fredlawl.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
* PCI: pciehp: Remove pciehp_debug usesBjorn Helgaas2019-05-091-8/+5
| | | | | | | | | | | | | We're about to convert pciehp to the dyndbg mechanism, which means we can eventually remove pciehp_debug. Replace uses of pciehp_debug with dbg() and ctrl_dbg(), which check pciehp_debug internally. Link: https://lore.kernel.org/lkml/20190509141456.223614-6-helgaas@kernel.org Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
* Merge branch 'pci/pm'Bjorn Helgaas2019-03-061-2/+15
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Blacklist Gigabyte X299 Root Port power management to fix Thunderbolt hotplug (Mika Westerberg) - Revert runtime PM suspend/resume callbacks that broke PME on network cable plug (Mika Westerberg) - Disable Data Link State Changed interrupts to prevent wakeup immediately after suspend (Mika Westerberg) * pci/pm: PCI/PME: Fix possible use-after-free on remove PCI/PME: Fix hotplug/sysfs remove deadlock in pcie_pme_remove() PCI: pciehp: Disable Data Link Layer State Changed event on suspend Revert "PCI/PME: Implement runtime PM callbacks" PCI: Blacklist power management of Gigabyte X299 DESIGNARE EX PCIe ports
| * PCI: pciehp: Disable Data Link Layer State Changed event on suspendMika Westerberg2019-02-151-2/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 0e157e528604 ("PCI/PME: Implement runtime PM callbacks") tried to solve an issue where the hierarchy immediately wakes up when it is transitioned into D3cold. However, it turns out to prevent PME propagation on some systems that do not support D3cold. I looked more closely at what might cause the immediate wakeup. It happens when the ACPI power resource of the root port is turned off. The AML code associated with the _OFF() method of the ACPI power resource starts a PCIe L2/L3 Ready transition and waits for it to complete. Right after the L2/L3 Ready transition is started the root port receives a PME from the downstream port. The simplest hierarchy where this happens looks like this: 00:1d.0 PCIe Root Port ^ | v 05:00.0 PCIe switch #1 upstream port 06:01.0 PCIe switch #1 downstream hotplug port ^ | v 08:00.0 PCIe switch #2 upstream port It seems that the PCIe link between the two switches, before PME_Turn_Off/PME_TO_Ack is complete for the whole hierarchy, goes inactive and triggers PME towards the root port bringing it back to D0. The L2/L3 Ready sequence is described in PCIe r4.0 spec sections 5.2 and 5.3.3 but unfortunately they do not state what happens if DLLSCE is enabled during the sequence. Disabling Data Link Layer State Changed event (DLLSCE) seems to prevent the issue and still allows the downstream hotplug port to notice when a device is plugged/unplugged. Link: https://bugzilla.kernel.org/show_bug.cgi?id=202593 Fixes: 0e157e528604 ("PCI/PME: Implement runtime PM callbacks") Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> CC: stable@vger.kernel.org # v4.20+
* | Merge branch 'pci/misc'Bjorn Helgaas2019-03-061-0/+2
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Mark expected switch fall-through (Mathieu Malaterre) - Use of_node_name_eq() for node name comparisons (Rob Herring) - Add ACS and pciehp quirks for HXT SD4800 (Shunyong Yang) - Consolidate Rohm Vendor ID definitions (Andy Shevchenko) - Use u32 (not __u32) for things not exposed to userspace (Logan Gunthorpe) - Fix locking semantics of bus and slot reset interfaces (Alex Williamson) - Update PCIEPORTBUS Kconfig help text (Hou Zhiqiang) * pci/misc: PCI: Update PCIEPORTBUS Kconfig help text PCI: Fix "try" semantics of bus and slot reset PCI: Clean up usage of __u32 type genirq/msi: Clean up usage of __u8/__u16 types PCI: Move Rohm Vendor ID to generic list PCI: pciehp: Add HXT quirk for Command Completed errata PCI: Add ACS quirk for HXT SD4800 PCI: Add HXT vendor ID PCI: Use of_node_name_eq() for node name comparisons PCI: Mark expected switch fall-through
| * | PCI: pciehp: Add HXT quirk for Command Completed errataShunyong Yang2019-02-021-0/+2
| |/ | | | | | | | | | | | | | | | | | | The HXT SD4800 PCI controller does not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. Add SD4800 to the quirk. Signed-off-by: Shunyong Yang <shunyong.yang@hxt-semitech.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: Joey Zheng <yu.zheng@hxt-semitech.com>
* / PCI: pciehp: Assign ctrl->slot_ctrl before writing it to hardwareMika Westerberg2019-01-151-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | Shameerali reported that running v4.20-rc1 as QEMU guest, the PCIe hotplug port times out during boot: pciehp 0000:00:01.0:pcie004: Timeout on hotplug command 0x03f1 (issued 1016 msec ago) pciehp 0000:00:01.0:pcie004: Timeout on hotplug command 0x03f1 (issued 1024 msec ago) pciehp 0000:00:01.0:pcie004: Failed to check link status pciehp 0000:00:01.0:pcie004: Timeout on hotplug command 0x02f1 (issued 2520 msec ago) The issue was bisected down to commit 720d6a671a6e ("PCI: pciehp: Do not handle events if interrupts are masked") and was further analyzed by the reporter to be caused by the fact that pciehp first updates the hardware and only then cache the ctrl->slot_ctrl in pcie_do_write_cmd(). If the interrupt happens before we cache the value, pciehp_isr() reads value 0 and decides that the interrupt was not meant for it causing the above timeout to trigger. Fix by moving ctrl->slot_ctrl assignment to happen before it is written to the hardware. Fixes: 720d6a671a6e ("PCI: pciehp: Do not handle events if interrupts are masked") Link: https://lore.kernel.org/linux-pci/5FC3163CFD30C246ABAA99954A238FA8387DD344@FRAEML521-MBX.china.huawei.com Reported-by: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
* PCI: pciehp: Do not handle events if interrupts are maskedMika Westerberg2018-10-021-2/+4
| | | | | | | | | | | | | PCIe native hotplug shares MSI vector with native PME so the interrupt handler might get called even the hotplug interrupt is masked. In that case we should not handle any events because the interrupt was not meant for us. Modify the PCIe hotplug interrupt handler to check this accordingly and bail out if it finds out that the interrupt was not about hotplug. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Lukas Wunner <lukas@wunner.de>
* PCI: pciehp: Disable hotplug interrupt during suspendMika Westerberg2018-10-021-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | When PCIe hotplug port is transitioned into D3hot, the link to the downstream component will go down. If hotplug interrupt generation is enabled when that happens, it will trigger immediately, waking up the system and bringing the link back up. To prevent this, disable hotplug interrupt generation when system suspend is entered. This does not prevent wakeup from low power states according to PCIe 4.0 spec section 6.7.3.4: Software enables a hot-plug event to generate a wakeup event by enabling software notification of the event as described in Section 6.7.3.1. Note that in order for software to disable interrupt generation while keeping wakeup generation enabled, the Hot-Plug Interrupt Enable bit must be cleared. So as long as we have set the slot event mask accordingly, wakeup should work even if slot interrupt is disabled. The port should trigger wake and then send PME to the root port when the PCIe hierarchy is brought back up. Limit this to systems using native PME mechanism to make sure older Apple systems depending on commit e3354628c376 ("PCI: pciehp: Support interrupts sent from D3hot") still continue working. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* PCI: Make link active reporting detection genericKeith Busch2018-10-021-20/+2
| | | | | | | | | | | | | The spec has timing requirements when waiting for a link to become active after a conventional reset. Implement those hard delays when waiting for an active link so pciehp and dpc drivers don't need to duplicate this. For devices that don't support data link layer active reporting, wait the fixed time recommended by the PCIe spec. Signed-off-by: Keith Busch <keith.busch@intel.com> [bhelgaas: changelog] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Sinan Kaya <okaya@kernel.org>
* PCI: hotplug: Embed hotplug_slotLukas Wunner2018-09-191-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the PCI hotplug core and its first user, cpqphp, were introduced in February 2002 with historic commit a8a2069f432c, cpqphp allocated a slot struct for its internal use plus a hotplug_slot struct to be registered with the hotplug core and linked the two with pointers: https://git.kernel.org/tglx/history/c/a8a2069f432c Nowadays, the predominant pattern in the tree is to embed ("subclass") such structures in one another and cast to the containing struct with container_of(). But it wasn't until July 2002 that container_of() was introduced with historic commit ec4f214232cf: https://git.kernel.org/tglx/history/c/ec4f214232cf pnv_php, introduced in 2016, did the right thing and embedded struct hotplug_slot in its internal struct pnv_php_slot, but all other drivers cargo-culted cpqphp's design and linked separate structs with pointers. Embedding structs is preferrable to linking them with pointers because it requires fewer allocations, thereby reducing overhead and simplifying error paths. Casting an embedded struct to the containing struct becomes a cheap subtraction rather than a dereference. And having fewer pointers reduces the risk of them pointing nowhere either accidentally or due to an attack. Convert all drivers to embed struct hotplug_slot in their internal slot struct. The "private" pointer in struct hotplug_slot thereby becomes unused, so drop it. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com> # drivers/pci/hotplug/rpa* Acked-by: Sebastian Ott <sebott@linux.ibm.com> # drivers/pci/hotplug/s390* Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # drivers/platform/x86 Cc: Len Brown <lenb@kernel.org> Cc: Scott Murray <scott@spiteful.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Oliver OHalloran <oliveroh@au1.ibm.com> Cc: Gavin Shan <gwshan@linux.vnet.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: Corentin Chary <corentin.chary@gmail.com> Cc: Darren Hart <dvhart@infradead.org>
* PCI: pciehp: Rename controller struct members for clarityLukas Wunner2018-09-191-3/+3
| | | | | | | | | | | | Of the members which were just moved from pciehp's slot struct to the controller struct, rename "lock" to "state_lock" and rename "work" to "button_work" for clarity. Perform the rename separately to the unification of the two structs per Sinan's request. No functional change intended. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Sinan Kaya <okaya@kernel.org>
* PCI: pciehp: Unify controller and slot structsLukas Wunner2018-09-191-79/+35
| | | | | | | | | | | | | | | | | | | | | | | | pciehp was originally introduced together with shpchp in a single commit, c16b4b14d980 ("PCI Hotplug: Add SHPC and PCI Express hot-plug drivers"): https://git.kernel.org/tglx/history/c/c16b4b14d980 shpchp supports up to 31 slots per controller, hence uses separate slot and controller structs. pciehp has a 1:1 relationship between slot and controller and therefore never required this separation. Nevertheless, because much of the code had been copy-pasted between the two drivers, pciehp likewise uses separate structs to this very day. The artificial separation of data structures adds unnecessary complexity and bloat to pciehp and requires constantly chasing pointers at runtime. Simplify the driver by merging struct slot into struct controller. Merge the slot constructor pcie_init_slot() and the destructor pcie_cleanup_slot() into the controller counterparts. No functional change intended. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
* PCI: pciehp: Tolerate Presence Detect hardwired to zeroLukas Wunner2018-09-191-6/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The WiGig Bus Extension (WBE) specification allows tunneling PCIe over IEEE 802.11. A product implementing this spec is the wil6210 from Wilocity (now part of Qualcomm Atheros). It integrates a PCIe switch with a wireless network adapter: 00.0-+ [1ae9:0101] Upstream Port +-00.0-+ [1ae9:0200] Downstream Port | +-00.0 [168c:0034] Atheros AR9462 Wireless Network Adapter +-02.0 [1ae9:0201] Downstream Port +-03.0 [1ae9:0201] Downstream Port Wirelessly attached devices presumably appear below the hotplug ports with device ID [1ae9:0201]. Oddly, the Downstream Port [1ae9:0200] leading to the wireless network adapter is likewise Hotplug Capable, but has its Presence Detect State bit hardwired to zero. Even if the Link Active bit is set, Presence Detect is zero, so this cannot be caused by in-band presence detection but only by broken hardware. pciehp assumes an empty slot if Presence Detect State is zero, regardless of Link Active being one. Consequently, up until v4.18 it removes the wireless network adapter in pciehp_resume(). From v4.19 it already does so in pciehp_probe(). Be lenient towards broken hardware and assume the slot is occupied if Link Active is set: Introduce pciehp_card_present_or_link_active() and use it in lieu of pciehp_get_adapter_status() everywhere, except in pciehp_handle_presence_or_link_change() whose log messages depend on which of Presence Detect State or Link Active is set. Remove the Presence Detect State check from __pciehp_enable_slot() because it is only called if either of Presence Detect State or Link Active is set. Caution: There is a possibility that broken hardware exists which has working Presence Detect but hardwires Link Active to one. On such hardware the slot will now incorrectly be considered always occupied. If such hardware is discovered, this commit can be rolled back and a quirk can be added which sets is_hotplug_bridge = 0 for [1ae9:0200]. Link: https://bugzilla.kernel.org/show_bug.cgi?id=200839 Reported-and-tested-by: David Yang <mmyangfl@gmail.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Rajat Jain <rajatja@google.com> Cc: Ashok Raj <ashok.raj@intel.com>
* PCI: pciehp: Drop hotplug_slot_ops wrappersLukas Wunner2018-09-171-2/+6
| | | | | | | | | | | | | pciehp's ->enable_slot, ->disable_slot, ->get_attention_status and ->reset_slot callbacks are currently implemented by wrapper functions that do nothing else but call down to a backend function. The backends are not called from anywhere else, so drop the wrappers and use the backends directly as callbacks, thereby shaving off a few lines of unnecessary code. No functional change intended. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
* PCI: pciehp: Drop unnecessary includesLukas Wunner2018-09-171-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Drop the following includes from pciehp source files which no longer use any of the included symbols: * <linux/sched/signal.h> in pciehp.h <linux/signal.h> in pciehp_hpc.c Added by commit de25968cc87c ("fix more missing includes") to accommodate for a call to signal_pending(). The call was removed by commit 262303fe329a ("pciehp: fix wait command completion"). * <linux/interrupt.h> in pciehp_core.c Added by historic commit f308a2dfbe63 ("PCI: add PCI Express Port Bus Driver subsystem") to accommodate for a call to free_irq(): https://git.kernel.org/tglx/history/c/f308a2dfbe63 The call was removed by commit 407f452b05f9 ("pciehp: remove unnecessary free_irq"). * <linux/time.h> in pciehp_core.c and pciehp_hpc.c Added by commit 34d03419f03b ("PCIEHP: Add Electro Mechanical Interlock (EMI) support to the PCIE hotplug driver."), which was reverted by commit bd3d99c17039 ("PCI: Remove untested Electromechanical Interlock (EMI) support in pciehp."). * <linux/module.h> in pciehp_ctrl.c, pciehp_hpc.c and pciehp_pci.c Added by historic commit c16b4b14d980 ("PCI Hotplug: Add SHPC and PCI Express hot-plug drivers"): https://git.kernel.org/tglx/history/c/c16b4b14d980 Module-related symbols were neither used back then in those files, nor are they used today. * <linux/slab.h> in pciehp_ctrl.c Added by commit 5a0e3ad6af86 ("include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h") to accommodate for calls to kmalloc(). The calls were removed by commit 0e94916e6091 ("PCI: pciehp: Handle events synchronously"). * "../pci.h" in pciehp_ctrl.c Added by historic commit 67f4660b72f2 ("PCI: ASPM patch for") to accommodate for usage of the global variable pcie_mch_quirk: https://git.kernel.org/tglx/history/c/67f4660b72f2 The global variable was removed by commit 0ba379ec0fb1 ("PCI: Simplify hotplug mch quirk"). Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>