[PATCH v4 17/25] drm/msm/dpu: Fail atomic_check if CWB and CDM are enabled

[Dmitry Baryshkov]

On Mon, Dec 16, 2024 at 04:43:28PM -0800, Jessica Zhang wrote:
> We cannot support both CWB and CDM simultaneously as this would require
> 2 CDM blocks and currently our hardware only supports 1 CDM block at
> most.

Why would CWB require a second CDM block? I think that YUV output over
DP (needs_cdm = true) and RGB output over WB (cwb_enabled = true) should
work. Am I wrong?

> 
> Thus return an error if both CWB and CDM are enabled.
> 
> Signed-off-by: Jessica Zhang <quic_jesszhan at quicinc.com>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> index 9bb920d28bae2706b3892c167fe2bec3fd8857f4..a6372eee916e8aba702bbefc3615d8882ddcaad9 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> @@ -1261,6 +1261,10 @@ static int dpu_crtc_assign_resources(struct drm_crtc *crtc, struct drm_crtc_stat
>  		return 0;
>  
>  	topology = dpu_crtc_get_topology(crtc, dpu_kms, crtc_state);
> +
> +	if (topology.cwb_enabled && topology.needs_cdm)
> +		return -EINVAL;
> +
>  	ret = dpu_rm_reserve(&dpu_kms->rm, global_state,
>  			     crtc, &topology);
>  	if (ret)
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry