mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity

drm/i915/display/lspcon: Increase LSPCON mode settle timeout 

This is to eliminate all cases of "*ERROR* LSPCON mode hasn't settled",
followed by link training errors. Intel engineers recommended increasing
this timeout and that does resolve the issue.

On some CometLake-based device designs the Parade PS175 takes more than
400ms to settle in PCON mode. 100 reboot trials on one device resulted
in a median settle time of 440ms and a maximum of 444ms. Even after
increasing the timeout to 500ms, 2% of devices still had this error. So
this increases the timeout to 800ms.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/9443
Signed-off-by: Pablo Ceballos <pceballos@google.com>
Signed-off-by: Niko Tsirakis <ntsirakis@google.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231002204709.761089-1-ntsirakis@google.com
This commit is contained in:
Niko Tsirakis 2023-10-02 20:47:09 +00:00 committed by Jani Nikula
parent 14aebb78b9
commit cf37c0979e
1 changed files with 14 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
drivers/gpu/drm/i915/display/intel_lspcon.c
View File

@ -153,6 +153,18 @@ static enum drm_lspcon_mode lspcon_get_current_mode(struct intel_lspcon *lspcon)
return current_mode;
}
static int lspcon_get_mode_settle_timeout(struct intel_lspcon *lspcon)
{
/*
* On some CometLake-based device designs the Parade PS175 takes more
* than 400ms to settle in PCON mode. 100 reboot trials on one device
* resulted in a median settle time of 440ms and a maximum of 444ms.
* Even after increasing the timeout to 500ms, 2% of devices still had
* this error. So this sets the timeout to 800ms.
*/
return lspcon->vendor == LSPCON_VENDOR_PARADE ? 800 : 400;
}
static enum drm_lspcon_mode lspcon_wait_mode(struct intel_lspcon *lspcon,
enum drm_lspcon_mode mode)
{
@ -167,7 +179,8 @@ static enum drm_lspcon_mode lspcon_wait_mode(struct intel_lspcon *lspcon,
drm_dbg_kms(&i915->drm, "Waiting for LSPCON mode %s to settle\n",
lspcon_mode_name(mode));
wait_for((current_mode = lspcon_get_current_mode(lspcon)) == mode, 400);
wait_for((current_mode = lspcon_get_current_mode(lspcon)) == mode,
lspcon_get_mode_settle_timeout(lspcon));
if (current_mode != mode)
drm_err(&i915->drm, "LSPCON mode hasn't settled\n");