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

[Abhinav Kumar]

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.barysh...@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()?

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?

With those two questions addressed,

Reviewed-by: Abhinav Kumar <quic_abhin...@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) {