[PATCH] drm/amdgpu/display: add dc feature mask for psr enablement

[Kazlauskas, Nicholas]

On 2019-10-22 9:33 a.m., Li, Roman wrote:
>> Any reason why we're skipping a flag here going from 0x2 to 0x8?
> 
> 0x4 is reserved for fractional pwm  mask:
> https://patchwork.freedesktop.org/patch/336923/

Ah, missed that patch. No problem then, feel free to go ahead with this.

Nicholas Kazlauskas

> 
> Thank you Nicholas for the review.
> 
> -----Original Message-----
> From: Kazlauskas, Nicholas <Nicholas.Kazlauskas at amd.com>
> Sent: Tuesday, October 22, 2019 8:39 AM
> To: Li, Roman <Roman.Li at amd.com>; amd-gfx at lists.freedesktop.org; Deucher, Alexander <Alexander.Deucher at amd.com>
> Cc: Wentland, Harry <Harry.Wentland at amd.com>; Lakha, Bhawanpreet <Bhawanpreet.Lakha at amd.com>; Li, Sun peng (Leo) <Sunpeng.Li at amd.com>
> Subject: Re: [PATCH] drm/amdgpu/display: add dc feature mask for psr enablement
> 
> On 2019-10-21 5:45 p.m., Roman.Li at amd.com wrote:
>> From: Roman Li <Roman.Li at amd.com>
>>
>> [Why]
>> Adding psr mask to dc features allows selectively disable/enable psr.
>> Current psr implementation may not work with non-pageflipping application.
>> Until resolved it should be disabled by default.
>>
>> [How]
>> Add dcfeaturemask for psr enablement. Disable by default.
>> To enable set amdgpu.dcfeaturemask=0x8 in grub kernel command line.
>>
>> Signed-off-by: Roman Li <Roman.Li at amd.com>
>> ---
>>    drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 3 ++-
>>    drivers/gpu/drm/amd/include/amd_shared.h          | 1 +
>>    2 files changed, 3 insertions(+), 1 deletion(-)
>>
>> 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 1cf4beb..0f08879 100644
>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> @@ -2424,7 +2424,8 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
>>    		} else if (dc_link_detect(link, DETECT_REASON_BOOT)) {
>>    			amdgpu_dm_update_connector_after_detect(aconnector);
>>    			register_backlight_device(dm, link);
>> -			amdgpu_dm_set_psr_caps(link);
>> +			if (amdgpu_dc_feature_mask & DC_PSR_MASK)
>> +				amdgpu_dm_set_psr_caps(link);
>>    		}
>>    
>>    
>> diff --git a/drivers/gpu/drm/amd/include/amd_shared.h
>> b/drivers/gpu/drm/amd/include/amd_shared.h
>> index 8889aac..1daa221 100644
>> --- a/drivers/gpu/drm/amd/include/amd_shared.h
>> +++ b/drivers/gpu/drm/amd/include/amd_shared.h
>> @@ -143,6 +143,7 @@ enum PP_FEATURE_MASK {
>>    enum DC_FEATURE_MASK {
>>    	DC_FBC_MASK = 0x1,
>>    	DC_MULTI_MON_PP_MCLK_SWITCH_MASK = 0x2,
>> +	DC_PSR_MASK = 0x8,
> 
> Can this just be 0x4 instead? Any reason why we're skipping a flag here going from 0x2 to 0x8?
> 
> You can still have my:
> 
> Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
> 
> but my preference would be on fixing this up to a 0x4 first in the commit message / DC_FEATURE_MASK.
> 
> Nicholas Kazlauskas
> 
>>    };
>>    
>>    enum amd_dpm_forced_level;
>>
>