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

[Jessica Zhang]

On 12/19/2024 9:44 PM, Dmitry Baryshkov wrote:
> 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?

Hey Dmitry,

No, I think your usecase should work. In that case, I can change this so 
that it only fails if both DP and WB are requesting CDM simultaneously.

Thanks,

Jessica Zhang

> 
>>
>> 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