> -----Original Message-----
> From: Ville Syrjälä <[email protected]>
> Sent: Wednesday, 2 September 2026 15.27
> To: Kahola, Mika <[email protected]>
> Cc: [email protected]; [email protected]
> Subject: Re: [PATCH v2 1/2] drm/i915/display: Reject flipq for pipe or timing
> changes
>
> On Wed, Sep 02, 2026 at 10:54:46AM +0000, Mika Kahola wrote:
> > Our flipq eligibility check let pipe, M/N and LRR changes through.
> > Reject those too, alongside the existing async flip/VRR/PSR/color/
> > modeset/fastset exclusions.
> >
> > v2:
> > - Drop the single-plane restriction, plane count doesn't matter (Ville)
> > - Drop the update_wm_pre/post check, dead code for flipq-capable hw (Ville)
> > - Drop the active/enabled planes check (Ville)
> >
> > Assisted-by: Copilot:claude-sonnet-5
> > Signed-off-by: Mika Kahola <[email protected]>
> > ---
> > drivers/gpu/drm/i915/display/intel_display.c | 43 ++++++++++++++++----
> > 1 file changed, 36 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_display.c
> > b/drivers/gpu/drm/i915/display/intel_display.c
> > index 553c60d452dd..f4b76a9547e3 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display.c
> > @@ -7369,6 +7369,41 @@ static void
> > intel_atomic_prepare_plane_clear_colors(struct intel_atomic_state *s
> > }
> > }
> >
> > +static bool intel_flipq_commit_is_eligible(struct intel_atomic_state
> > *state,
> > + struct intel_crtc *crtc)
> > +{
> > + struct intel_display *display = to_intel_display(state);
> > + const struct intel_crtc_state *new_crtc_state =
> > + intel_atomic_get_new_crtc_state(state, crtc);
> > +
> > + if (!intel_flipq_supported(display))
> > + return false;
> > +
> > + if (intel_crtc_needs_modeset(new_crtc_state) ||
> > + intel_crtc_needs_fastset(new_crtc_state) ||
> > + intel_crtc_needs_color_update(new_crtc_state))
> > + return false;
> > +
> > + if (!new_crtc_state->update_planes)
> > + return false;
>
> Why?
I though of case with joiner where we would have one update_planes true and the
other one update_planes false but I searched a bit deeper and it seems I was
wrong. No need to check the planes either.
>
> > +
> > + if (new_crtc_state->do_async_flip ||
> > + new_crtc_state->vrr.enable ||
> > + new_crtc_state->has_psr)
> > + return false;
> > +
> > + /*
> > + * Flipq is only suitable for simple queued plane updates that do
> > + * not require additional pipe or timing programming.
> > + */
> > + if (new_crtc_state->update_pipe ||
> > + new_crtc_state->update_m_n ||
> > + new_crtc_state->update_lrr)
> > + return false;
>
> That is all covered by intel_crtc_needs_fastset().
Yes, Sashiko noticed this one too and I dropped these checks.
There is no need for the patch here, so I will drop this.
Thanks for the review!
-Mika-
>
> > +
> > + return true;
> > +}
> > +
> > static void intel_atomic_dsb_prepare(struct intel_atomic_state *state,
> > struct intel_crtc *crtc)
> > {
> > @@ -7384,13 +7419,7 @@ static void intel_atomic_dsb_prepare(struct
> > intel_atomic_state *state,
> >
> > /* FIXME deal with everything */
> > new_crtc_state->use_flipq =
> > - intel_flipq_supported(display) &&
> > - !new_crtc_state->do_async_flip &&
> > - !new_crtc_state->vrr.enable &&
> > - !new_crtc_state->has_psr &&
> > - !intel_crtc_needs_modeset(new_crtc_state) &&
> > - !intel_crtc_needs_fastset(new_crtc_state) &&
> > - !intel_crtc_needs_color_update(new_crtc_state);
> > + intel_flipq_commit_is_eligible(state, crtc);
> >
> > new_crtc_state->use_dsb =
> > !new_crtc_state->use_flipq &&
> > --
> > 2.43.0
>
> --
> Ville Syrjälä
> Intel
