From 89c290ea758911e660878e26270e084d862c03b0 Mon Sep 17 00:00:00 2001 From: Kai-Heng Feng Date: Fri, 21 Jul 2023 23:21:43 +0800 Subject: ACPI: video: Put ACPI video and its child devices into D0 on boot Screen brightness can only be changed once on HP ZBook Fury 16 G10. The vendor reports that the issue is related to the fact that Linux doesn't invoke _PS0 at boot for all ACPI devices, as expected by the platform firmware: Scope (\_SB.PC00.GFX0) { Scope (DD1F) { Method (_PS0, 0, Serialized) // _PS0: Power State 0 { If (CondRefOf (\_SB.PC00.LPCB.EC0.SSBC)) { \_SB.PC00.LPCB.EC0.SSBC () } } ... } ... } The \_SB.PC00.GFX0.DD1F is the panel device, and its _PS0 needs to be executed at the initialization time to make the brightness control work properly. _PS0 is not evaluated for this device, because _PSC is missing, which violates the ACPI specification (ACPI 6.5, section 7.3.6). Commit b3785492268f ("ACPI / PM: Do not power manage devices in unknown initial states") tried to work around missing _PSC on platforms with defective firmware, but got reverted due to a regression. So the safest approach is to use acpi_device_fix_up_power_extended() to put ACPI video and its child devices to D0 to address the issue at hand. Link: https://bugzilla.kernel.org/show_bug.cgi?id=217683 Signed-off-by: Kai-Heng Feng Reviewed-by: Hans de Goede [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki --- drivers/acpi/acpi_video.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'drivers/acpi/acpi_video.c') diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c index 62f4364e4460..1732780a672b 100644 --- a/drivers/acpi/acpi_video.c +++ b/drivers/acpi/acpi_video.c @@ -2027,6 +2027,12 @@ static int acpi_video_bus_add(struct acpi_device *device) if (error) goto err_put_video; + /* + * HP ZBook Fury 16 G10 requires ACPI video's child devices have _PS0 + * evaluated to have functional panel brightness control. + */ + acpi_device_fix_up_power_extended(device); + pr_info("%s [%s] (multi-head: %s rom: %s post: %s)\n", ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device), video->flags.multihead ? "yes" : "no", -- cgit v1.2.3