Re: [PATCH] drm/msm/dp: no dp_hpd_unplug_handle() required for eDP

[Kuogee Hsieh]

On 6/23/2022 5:09 PM, Stephen Boyd wrote:
> Quoting Kuogee Hsieh (2022-06-23 16:34:16)
> > eDP implementation does not reuried to support hpd signal. Therefore
> s/reuried/require/
>
> > it only has either ST_DISPLAY_OFF or ST_CONNECTED state during normal
> > operation. This patch remove unnecessary dp_hpd_unplug_handle() for
> > eDP but still keep dp_hpd_plug_handle() to support eDP to either
> > booting up or resume from ST_DISCONNECTED state.
> I take it that making this change also fixes a glitch seen on the eDP
> panel when a second modeset happens? Can you add that detail to the
> commit text? The way it reads makes it sound like this is purely a
> cleanup patch, but then there's a Fixes tag so it must be a bug fix or
> worthy optimization, neither of which is described.

no, this patch will not fix edp (primary display) corruption issue.

This patch is pure clean up edp.

I will submit fixes edp corruption issue at other patch.

> > Fixes: 391c96ff0555 ("drm/msm/dp: Support only IRQ_HPD and REPLUG interrupts for eDP")
> > Signed-off-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/msm/dp/dp_display.c | 5 +----
> >   1 file changed, 1 insertion(+), 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> > index da5c03a..ef9794e 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_display.c
> > +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> > @@ -1666,7 +1666,7 @@ void dp_bridge_enable(struct drm_bridge *drm_bridge)
> >                  return;
> >          }
> >
> > -       if (dp->is_edp)
> > +       if (dp->is_edp && dp_display->hpd_state == ST_DISCONNECTED)
> >                  dp_hpd_plug_handle(dp_display, 0);
> >
> >          mutex_lock(&dp_display->event_mutex);
> > @@ -1737,9 +1737,6 @@ void dp_bridge_post_disable(struct drm_bridge *drm_bridge)
> >
> >          dp_display = container_of(dp, struct dp_display_private, dp_display);
> >
> > -       if (dp->is_edp)
> > -               dp_hpd_unplug_handle(dp_display, 0);
> dp_hpd_unplug_handle() has a !edp check, and from what I can tell after
> this patch that condition will always trigger? But then I wonder why we
> aren't masking the irqs for hpd when the eDP display is disabled.
> Shouldn't we at least be doing that so that we don't get spurious hpd
> irqs when the eDP display is off or on the path to suspend where I
> suspect the power may be removed from the panel?