On Mon, 02 Oct 2023, Niko Tsirakis <ntsirakis@xxxxxxxxxx> 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. > > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/9443 > Signed-off-by: Pablo Ceballos <pceballos@xxxxxxxxxx> > Signed-off-by: Niko Tsirakis <ntsirakis@xxxxxxxxxx> Thanks for the patch, pushed to drm-intel-next. BR, Jani. > --- > 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"); -- Jani Nikula, Intel
