[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.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()?

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_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) {
>