On 6/15/2023 5:24 AM, Pablo Ceballos wrote:
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.
In one of the gitlab issue, it was tried with 1000ms as well, situation
did improve, but issue didn't get fully resolved. [1].
I was wondering if trying to set LS/PCON mode multiple time will have
any effect.
Unfortunately I do not have access to machine with Parade LSPCON chip,
had suggested in yet another git lab issue [2].
I have a patch for this, sent to try-bot, though not sent to intel-gfx
yet [3].
The timeout value was already increased from 100 ms to 400 ms earlier too.
If there is indeed no other way, perhaps need to have this solution.
[1] https://gitlab.freedesktop.org/drm/intel/-/issues/4516#note_1406500
[2] https://gitlab.freedesktop.org/drm/intel/-/issues/4458#note_1922654
[3] Patch :
https://patchwork.freedesktop.org/patch/538819/?series=118208&rev=1
Regards,
Ankit
Signed-off-by: Pablo Ceballos <pceballos@xxxxxxxxxx>
---
Changelog since v1:
- Added more details in the commit message
drivers/gpu/drm/i915/display/intel_lspcon.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/display/intel_lspcon.c b/drivers/gpu/drm/i915/display/intel_lspcon.c
index bb3b5355a0d9..d7299fdc43ad 100644
--- a/drivers/gpu/drm/i915/display/intel_lspcon.c
+++ b/drivers/gpu/drm/i915/display/intel_lspcon.c
@@ -167,7 +167,7 @@ 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, 800);
if (current_mode != mode)
drm_err(&i915->drm, "LSPCON mode hasn't settled\n");
