[PATCH v2 7/9] drm/msm/dpu: check for overflow in _dpu_crtc_setup_lm_bounds()

[Dmitry Baryshkov]

On Mon, 3 Jun 2024 at 23:57, Abhinav Kumar <quic_abhinavk at quicinc.com> wrote:
>
>
>
> On 6/2/2024 2:39 PM, Dmitry Baryshkov wrote:
> > Check in _dpu_crtc_setup_lm_bounds() that CRTC width is not overflowing
> > LM requirements.
> >
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> > ---
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 15 ++++++++++++---
> >   1 file changed, 12 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> > index e3b1e5f55a92..c5e874a3656a 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> > @@ -711,12 +711,13 @@ void dpu_crtc_complete_commit(struct drm_crtc *crtc)
> >       _dpu_crtc_complete_flip(crtc);
> >   }
> >
> > -static void _dpu_crtc_setup_lm_bounds(struct drm_crtc *crtc,
> > +static int _dpu_crtc_setup_lm_bounds(struct drm_crtc *crtc,
> >               struct drm_crtc_state *state)
>
> Perhaps now we need to rename this to _dpu_crtc_setup_and_check_lm_bounds()?

Ack, I'll rename it.

>
> Also, prior to this change, we never had a bounds check for each LM
> which we should have had . Does this qualify for a Fixes tag?

Probably no. We currently have a limit in the drm_mode_config, which
ensures that the CRTC isn't too wide.

>
> With those two questions addressed,
>
> Reviewed-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
>
> >   {
> >       struct dpu_crtc_state *cstate = to_dpu_crtc_state(state);
> >       struct drm_display_mode *adj_mode = &state->adjusted_mode;
> >       u32 crtc_split_width = adj_mode->hdisplay / cstate->num_mixers;
> > +     struct dpu_kms *dpu_kms = _dpu_crtc_get_kms(crtc);
> >       int i;
> >
> >       for (i = 0; i < cstate->num_mixers; i++) {
> > @@ -727,7 +728,12 @@ static void _dpu_crtc_setup_lm_bounds(struct drm_crtc *crtc,
> >               r->y2 = adj_mode->vdisplay;
> >
> >               trace_dpu_crtc_setup_lm_bounds(DRMID(crtc), i, r);
> > +
> > +             if (drm_rect_width(r) > dpu_kms->catalog->caps->max_mixer_width)
> > +                     return -E2BIG;
> >       }
>
> > +
> > +     return 0;
> >   }
> >
> >   static void _dpu_crtc_get_pcc_coeff(struct drm_crtc_state *state,
> > @@ -1195,8 +1201,11 @@ static int dpu_crtc_atomic_check(struct drm_crtc *crtc,
> >       if (crtc_state->active_changed)
> >               crtc_state->mode_changed = true;
> >
> > -     if (cstate->num_mixers)
> > -             _dpu_crtc_setup_lm_bounds(crtc, crtc_state);
> > +     if (cstate->num_mixers) {
> > +             rc = _dpu_crtc_setup_lm_bounds(crtc, crtc_state);
> > +             if (rc)
> > +                     return rc;
> > +     }
> >
> >       /* FIXME: move this to dpu_plane_atomic_check? */
> >       drm_atomic_crtc_state_for_each_plane_state(plane, pstate, crtc_state) {
> >



-- 
With best wishes
Dmitry