On Tue, 2023-05-30 at 09:06 +0000, Murthy, Arun R wrote:
> > -----Original Message-----
> > From: Intel-gfx <intel-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf
> > Of Jouni
> > Högander
> > Sent: Monday, May 29, 2023 6:30 PM
> > To: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> > Subject: [PATCH] drm/i915: Use 18 fast wake fast wake
> > AUX sync
> > len
> >
> > HW default for wake sync pulses is 18. 10 precarge and 8 preamble.
> > There is
> > no reason to change this especially as it is causing problems with
> > certain eDP
> > panels.
> >
> > Signed-off-by: Jouni Högander <jouni.hogander@xxxxxxxxx>
> > Fixes: 605f7c731333 ("drm/i915: Fix fast wake AUX sync len")
> > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8475
> > ---
> > drivers/gpu/drm/i915/display/intel_dp_aux.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c
> > b/drivers/gpu/drm/i915/display/intel_dp_aux.c
> > index 0c27db8ae4f1..197c6e81db14 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp_aux.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c
> > @@ -129,7 +129,7 @@ static int intel_dp_aux_sync_len(void)
> >
> > static int intel_dp_aux_fw_sync_len(void) {
> > - int precharge = 16; /* 10-16 */
> > + int precharge = 10; /* 10-16 */
>
> Is this change required in intel_dp_aux_sync_len() as well?
That is a good question. The issue is triggered with certain PSR panels
and only fast wake sync len impacts PSR sequence -> definetely it's not
in scope of this patch.
BR,
Jouni Högander
>
> Thanks and Regards,
> Arun R Murthy
> --------------------
>
> > int preamble = 8;
> >
> > return precharge + preamble;
> > --
> > 2.34.1
>
