diff options
| author | Mika Westerberg <mika.westerberg@linux.intel.com> | 2022-04-01 16:24:28 +0200 |
|---|---|---|
| committer | Mika Westerberg <mika.westerberg@linux.intel.com> | 2022-04-19 09:26:18 +0200 |
| commit | 9d2d0a5cf0ca063f417681cc33e767ce52615286 (patch) | |
| tree | a5f8c4deb919a2e471e8ba39290963f4717345cc /drivers/thunderbolt/tunnel.c | |
| parent | thunderbolt: Dump path config space entries during discovery (diff) | |
| download | linux-9d2d0a5cf0ca063f417681cc33e767ce52615286.tar.xz linux-9d2d0a5cf0ca063f417681cc33e767ce52615286.zip | |
thunderbolt: Use different lane for second DisplayPort tunnel
Brad reported that on Apple hardware with Light Ridge or Falcon Ridge
controller, plugging in a chain of Thunderbolt displays (Light Ridge
based controllers) causes all kinds of tearing and flickering. The
reason for this is that on Thunderbolt 1 hardware there is no lane
bonding so we have two independent 10 Gb/s lanes, and currently Linux
tunnels both displays through the lane 1. This makes the displays to
share the 10 Gb/s bandwidth which may not be enough for higher
resolutions.
For this reason make the second tunnel go through the lane 0 instead.
This seems to match what the macOS connection manager is also doing.
Reported-by: Brad Campbell <lists2009@fnarfbargle.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Brad Campbell <lists2009@fnarfbargle.com>
Diffstat (limited to 'drivers/thunderbolt/tunnel.c')
| -rw-r--r-- | drivers/thunderbolt/tunnel.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/drivers/thunderbolt/tunnel.c b/drivers/thunderbolt/tunnel.c index 118742ec93ed..8ccd70920b6a 100644 --- a/drivers/thunderbolt/tunnel.c +++ b/drivers/thunderbolt/tunnel.c @@ -858,6 +858,7 @@ err_free: * @tb: Pointer to the domain structure * @in: DP in adapter port * @out: DP out adapter port + * @link_nr: Preferred lane adapter when the link is not bonded * @max_up: Maximum available upstream bandwidth for the DP tunnel (%0 * if not limited) * @max_down: Maximum available downstream bandwidth for the DP tunnel @@ -869,8 +870,8 @@ err_free: * Return: Returns a tb_tunnel on success or NULL on failure. */ struct tb_tunnel *tb_tunnel_alloc_dp(struct tb *tb, struct tb_port *in, - struct tb_port *out, int max_up, - int max_down) + struct tb_port *out, int link_nr, + int max_up, int max_down) { struct tb_tunnel *tunnel; struct tb_path **paths; @@ -894,21 +895,21 @@ struct tb_tunnel *tb_tunnel_alloc_dp(struct tb *tb, struct tb_port *in, paths = tunnel->paths; path = tb_path_alloc(tb, in, TB_DP_VIDEO_HOPID, out, TB_DP_VIDEO_HOPID, - 1, "Video"); + link_nr, "Video"); if (!path) goto err_free; tb_dp_init_video_path(path); paths[TB_DP_VIDEO_PATH_OUT] = path; path = tb_path_alloc(tb, in, TB_DP_AUX_TX_HOPID, out, - TB_DP_AUX_TX_HOPID, 1, "AUX TX"); + TB_DP_AUX_TX_HOPID, link_nr, "AUX TX"); if (!path) goto err_free; tb_dp_init_aux_path(path); paths[TB_DP_AUX_PATH_OUT] = path; path = tb_path_alloc(tb, out, TB_DP_AUX_RX_HOPID, in, - TB_DP_AUX_RX_HOPID, 1, "AUX RX"); + TB_DP_AUX_RX_HOPID, link_nr, "AUX RX"); if (!path) goto err_free; tb_dp_init_aux_path(path); |