On Fri, Mar 11, 2022 at 01:05:49PM +0000, Souza, Jose wrote:
> On Thu, 2022-03-10 at 23:52 +0200, Ville Syrjälä wrote:
> > On Thu, Mar 10, 2022 at 12:05:17PM -0800, José Roberto de Souza wrote:
> > > Commit 13ea6db2cf24 ("drm/i915/edp: Ignore short pulse when panel
> > > powered off") completely broke short pulse handling for eDP as it is
> > > usually generated by sink when it is displaying image and there is
> > > some error or status that source needs to handle.
> > >
> > > When power panel is enabled, this state is enough to power aux
> > > transactions and VDD override is disabled, so intel_pps_have_power()
> > > is always returning false causing short pulses to be ignored.
> >
> > I think the times that we use the vdd override should be
> > limited to:
> > - aux transfers while the display off
> > - potentially short periods of time during the modeset sequence
> >
> > So I guess what you're saying here is that during those times
> > some panel is triggering an IRQ_HPD which, if ignored, causes
> > some problem for us?
>
> No, not in those times.
> When panel is on scanning out frames, PPS is enabled and VDD is disabled.
> So any short pulse HPD was being ignored because (edp_have_panel_power() && edp_have_panel_vdd()) is always false.
>
> >
> > >
> > > So here better naming this function that intends to check if aux
> > > lines are powered to avoid the endless cycle mentioned in the commit
> > > being fixed and fixing the check for what it is intended.
> > >
> > > Fixes: 13ea6db2cf24 ("drm/i915/edp: Ignore short pulse when panel powered off")
> > > Cc: Anshuman Gupta <anshuman.gupta@xxxxxxxxx>
> > > Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
> > > Cc: Uma Shankar <uma.shankar@xxxxxxxxx>
> > > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> > > Signed-off-by: José Roberto de Souza <jose.souza@xxxxxxxxx>
> > > ---
> > > drivers/gpu/drm/i915/display/intel_dp.c | 2 +-
> > > drivers/gpu/drm/i915/display/intel_pps.c | 4 ++--
> > > drivers/gpu/drm/i915/display/intel_pps.h | 2 +-
> > > 3 files changed, 4 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> > > index 619546441eae5..b029b064000d6 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > > @@ -4867,7 +4867,7 @@ intel_dp_hpd_pulse(struct intel_digital_port *dig_port, bool long_hpd)
> > > struct intel_dp *intel_dp = &dig_port->dp;
> > >
> > > if (dig_port->base.type == INTEL_OUTPUT_EDP &&
> > > - (long_hpd || !intel_pps_have_power(intel_dp))) {
> > > + (long_hpd || !intel_pps_have_vdd_power(intel_dp))) {
> > > /*
> > > * vdd off can generate a long/short pulse on eDP which
> > > * would require vdd on to handle it, and thus we
> > > diff --git a/drivers/gpu/drm/i915/display/intel_pps.c b/drivers/gpu/drm/i915/display/intel_pps.c
> > > index 9c986e8932f87..d3e6083ad5b79 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_pps.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_pps.c
> > > @@ -1075,13 +1075,13 @@ static void intel_pps_vdd_sanitize(struct intel_dp *intel_dp)
> > > edp_panel_vdd_schedule_off(intel_dp);
> > > }
> > >
> > > -bool intel_pps_have_power(struct intel_dp *intel_dp)
> > > +bool intel_pps_have_vdd_power(struct intel_dp *intel_dp)
> > > {
> > > intel_wakeref_t wakeref;
> > > bool have_power = false;
> > >
> > > with_intel_pps_lock(intel_dp, wakeref) {
> > > - have_power = edp_have_panel_power(intel_dp) &&
Ah, that s/&&/||/ is the bug you're fixing. I didn't even notice,
probably because of the broken indentation in the code here. I just
read it and thought it only checks for panel power and not vdd.
Can you also fix up the indentation a bit so the code doesn't
look so weird?
I think I'd call the function intel_pps_have_panel_power_or_vdd()
(or something along those lines) to make it clear what it does.
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> > > + have_power = edp_have_panel_power(intel_dp) ||
> > > edp_have_panel_vdd(intel_dp);
> > > }
> > >
> > > diff --git a/drivers/gpu/drm/i915/display/intel_pps.h b/drivers/gpu/drm/i915/display/intel_pps.h
> > > index fbb47f6f453e4..948523ce32417 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_pps.h
> > > +++ b/drivers/gpu/drm/i915/display/intel_pps.h
> > > @@ -37,7 +37,7 @@ void intel_pps_vdd_on(struct intel_dp *intel_dp);
> > > void intel_pps_on(struct intel_dp *intel_dp);
> > > void intel_pps_off(struct intel_dp *intel_dp);
> > > void intel_pps_vdd_off_sync(struct intel_dp *intel_dp);
> > > -bool intel_pps_have_power(struct intel_dp *intel_dp);
> > > +bool intel_pps_have_vdd_power(struct intel_dp *intel_dp);
> > > void intel_pps_wait_power_cycle(struct intel_dp *intel_dp);
> > >
> > > void intel_pps_init(struct intel_dp *intel_dp);
> > > --
> > > 2.35.1
> >
>
--
Ville Syrjälä
Intel
