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 <pcebal...@google.com> Signed-off-by: Niko Tsirakis <ntsira...@google.com> --- drivers/gpu/drm/i915/display/intel_lspcon.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/display/intel_lspcon.c b/drivers/gpu/drm/i915/display/intel_lspcon.c index dc1b35559afd..92536482e657 100644 --- a/drivers/gpu/drm/i915/display/intel_lspcon.c +++ b/drivers/gpu/drm/i915/display/intel_lspcon.c @@ -116,6 +116,18 @@ 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) { @@ -128,7 +140,8 @@ static enum drm_lspcon_mode lspcon_wait_mode(struct intel_lspcon *lspcon, DRM_DEBUG_KMS("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_ERROR("LSPCON mode hasn't settled\n"); -- 2.42.0.582.g8ccd20d70d-goog
