[PATCH v2] drm/amdgpu: fix that issue that the number of the crtc of the 3250c is not correct

[Paul Menzel]

[Cc: Remove undeliverable Chun Ming Zhou <mailto:David1.Zhou at amd.com>]

Am 30.03.22 um 08:34 schrieb Paul Menzel:
> Dear Tsung-Hua,
> 
> 
> Thank you for your patch.
> 
> Am 30.03.22 um 04:46 schrieb Ryan Lin:
> 
> The commit message summary is quite long and confusing. Maybe:
> 
> Use 3 CRTC for 3250c to get internal display working
> 
>> [Why]
>> External displays take priority over internal display when there are 
>> fewer
>> display controllers than displays.
> 
> This causes the internal display to not work on the Chromebook google/zork.
> 
>> [How]
>> The root cause is because of that number of the crtc is not correct.
> 
> The root cause is the incorrect number of four configured CRTCs.
> 
>> The number of the crtc on the 3250c is 3, but on the 3500c is 4.
>> On the source code, we can see that number of the crtc has been fixed 
>> at 4.
>> Needs to set the num_crtc to 3 for 3250c platform.
> 
> Please do not wrap lines after each sentence, and use a text width of 75 
> characters.
> 
>> v2:
>>     - remove unnecessary comments and Id
>>
>> Signed-off-by: Ryan Lin <tsung-hua.lin at amd.com>
>>
>> ---
>>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 12 +++++++++---
>>   1 file changed, 9 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c 
>> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> index 40c91b448f7da..455a2c45e8cda 100644
>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> @@ -2738,9 +2738,15 @@ static int dm_early_init(void *handle)
>>           break;
>>   #if defined(CONFIG_DRM_AMD_DC_DCN1_0)
>>       case CHIP_RAVEN:
>> -        adev->mode_info.num_crtc = 4;
>> -        adev->mode_info.num_hpd = 4;
>> -        adev->mode_info.num_dig = 4;
>> +        if (adev->rev_id >= 8) {
> 
> Is there some define for that number? Maybe add a comment, that it’s for 
> 3250c?
> 
> 
> Kind regards,
> 
> Paul
> 
> 
>> +            adev->mode_info.num_crtc = 3;
>> +            adev->mode_info.num_hpd = 3;
>> +            adev->mode_info.num_dig = 3;
>> +        } else {
>> +            adev->mode_info.num_crtc = 4;
>> +            adev->mode_info.num_hpd = 4;
>> +            adev->mode_info.num_dig = 4;
>> +        }
>>           break;
>>   #endif
>>   #if defined(CONFIG_DRM_AMD_DC_DCN2_0)