[Intel-gfx] [PATCH v2] drm/i915: Do a better job at disabling primary plane in the noatomic case.

[Tomas M]

Hello,

Is there any special reason this has not been merged yet?

Regards

Tomas

On Tue, Dec 1, 2015 at 6:07 AM, Jani Nikula <jani.nikula at linux.intel.com>
wrote:

> On Mon, 23 Nov 2015, Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> wrote:
> > Op 13-11-15 om 14:28 schreef Ander Conselvan De Oliveira:
> >> On Thu, 2015-11-12 at 14:58 +0100, Maarten Lankhorst wrote:
> >>> Op 12-11-15 om 14:37 schreef Ander Conselvan De Oliveira:
> >>>> On Wed, 2015-11-11 at 15:36 +0100, Maarten Lankhorst wrote:
> >>>>> When disable_noatomic is called plane_mask is not reliable yet,
> >>>>> and plane_state->visible = true even after disabling the primary
> plane.
> >>>> So the stale value of plane_state->visible causes a subsequent
> modeset to
> >>>> enable
> >>>> the primary again?
> >>> Probably not because it would get recalculated in calc_changes, but it
> should
> >>> really be set to false afterwards.
> >> So basically I didn't understand how the wrong value of
> plane_state->visible
> >> causes the bug that was mentioned. I think a brief explanation in the
> commit
> >> message would be good.
> > Well, apply with git am --scissors. Same patch but mentioning this.
> >
> > Is this better?
>
> Ander, ping?
>
> BR,
> Jani.
>
> > ---->8-----
> >
> > When disable_noatomic is called plane_mask is not correct yet,
> > and plane_state->visible = true is left as true after disabling
> > the primary plane.
> >
> > Other planes are already disabled as part of crtc sanitization, only the
> > primary is left active. But the plane_mask is not updated here. It gets
> updated
> > during fb takeover in modeset_gem_init, or set to the new value on
> resume.
> >
> > This means that to disable the primary plane 1 <<
> drm_plane_index(primary)
> > needs to be used.
> >
> > Afterwards because the crtc is no longer active it's forbidden to keep
> > plane_state->visible set, or a WARN_ON in intel_plane_atomic_calc_changes
> > triggers. There are other code points that rely on accurate
> plane_state->visible
> > too, so make sure the bool is cleared.
> >
> >
> > The other planes are already disabled in intel_sanitize_crtc, so
> > they don't have to be handled here.
> >
> > Cc: stable at vger.kernel.org #v4.3, v4.2?
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92655
> > Tested-by: Tomas Mezzadra <tmezzadra at gmail.com>
> > Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_display.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_display.c
> b/drivers/gpu/drm/i915/intel_display.c
> > index b5f7493213b7..bc3282ab5ed2 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -6267,9 +6267,11 @@ static void intel_crtc_disable_noatomic(struct
> drm_crtc *crtc)
> >               WARN_ON(intel_crtc->unpin_work);
> >
> >               intel_pre_disable_primary(crtc);
> > +
> > +             intel_crtc_disable_planes(crtc, 1 <<
> drm_plane_index(crtc->primary));
> > +             to_intel_plane_state(crtc->primary->state)->visible =
> false;
> >       }
> >
> > -     intel_crtc_disable_planes(crtc, crtc->state->plane_mask);
> >       dev_priv->display.crtc_disable(crtc);
> >       intel_crtc->active = false;
> >       intel_update_watermarks(crtc);
> > -- 2.1.0
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> --
> Jani Nikula, Intel Open Source Technology Center
>
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