On Wed, 16 Aug 2023, Pablo Ceballos <pceballos@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. > > Signed-off-by: Pablo Ceballos <pceballos@xxxxxxxxxx> Please file the issue at [1] as requested before, and reference it in the commit message. [1] https://gitlab.freedesktop.org/drm/intel/-/issues/new > --- > > V2: Added more details in the commit message > V3: Only apply the increased timeout if the vendor is Parade > > drivers/gpu/drm/i915/display/intel_lspcon.c | 21 ++++++++++++++++++++- > 1 file changed, 20 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_lspcon.c b/drivers/gpu/drm/i915/display/intel_lspcon.c > index bb3b5355a0d9..b07eab84cc63 100644 > --- a/drivers/gpu/drm/i915/display/intel_lspcon.c > +++ b/drivers/gpu/drm/i915/display/intel_lspcon.c > @@ -153,6 +153,24 @@ static enum drm_lspcon_mode lspcon_get_current_mode(struct intel_lspcon *lspcon) > return current_mode; > } > > +static u32 lspcon_get_mode_settle_timeout(struct intel_lspcon *lspcon) > +{ > + u32 timeout_ms = 400; Please use plain int for plain numbers. There's nothing u32 about this. > + > + /* > + * 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. > + */ > + if (lspcon->vendor == LSPCON_VENDOR_PARADE) > + timeout_ms = 800; > + > + return timeout_ms; All of the above is just return lspcon->vendor == LSPCON_VENDOR_PARADE ? 800 : 400; BR, Jani. > +} > + > + > static enum drm_lspcon_mode lspcon_wait_mode(struct intel_lspcon *lspcon, > enum drm_lspcon_mode mode) > { > @@ -167,7 +185,8 @@ 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"); -- Jani Nikula, Intel
