[PATCH] drm/amd: Add debug mask for subviewport mclk switch

[Aurabindo Pillai]

On 2022-07-05 15:53, Harry Wentland wrote:
> 
> 
> On 2022-06-28 17:26, Aurabindo Pillai wrote:
>> [Why&How]
>> Expose a new debugfs enum to force a subviewport memory clock switch
>> to facilitate easy testing.
>>
> 
> Does this force a single switch? Or at regular intervals?

If this debug option is set, each time a MCLK switch happens, a SubVP 
sequences shall be initiated. That is, during the MCLK switch the 
scanout shall be from the Subviewport memory. Setting this option doesnt 
trigger an MCLK switch though.

> 
> It would be useful to describe a bit better what it does.

Will keep that in mind, thanks! Unfortunately I merged it already since 
I got the ack last week.

> 
>> Signed-off-by: Aurabindo Pillai <aurabindo.pillai at amd.com>
> 
> Either way, since this is for debug purposes only this is
> Reviewed-by: Harry Wentland <harry.wentland at amd.com>
> 
> Harry
> 
>> ---
>>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 3 +++
>>   drivers/gpu/drm/amd/include/amd_shared.h          | 1 +
>>   2 files changed, 4 insertions(+)
>>
>> 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 c9145864ed2b..7a034ca95be2 100644
>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> @@ -1559,6 +1559,9 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
>>   	if (amdgpu_dc_debug_mask & DC_DISABLE_CLOCK_GATING)
>>   		adev->dm.dc->debug.disable_clock_gate = true;
>>   
>> +	if (amdgpu_dc_debug_mask & DC_FORCE_SUBVP_MCLK_SWITCH)
>> +		adev->dm.dc->debug.force_subvp_mclk_switch = true;
>> +
>>   	r = dm_dmub_hw_init(adev);
>>   	if (r) {
>>   		DRM_ERROR("DMUB interface failed to initialize: status=%d\n", r);
>> diff --git a/drivers/gpu/drm/amd/include/amd_shared.h b/drivers/gpu/drm/amd/include/amd_shared.h
>> index bcdf7453a403..b1c55dd7b498 100644
>> --- a/drivers/gpu/drm/amd/include/amd_shared.h
>> +++ b/drivers/gpu/drm/amd/include/amd_shared.h
>> @@ -247,6 +247,7 @@ enum DC_DEBUG_MASK {
>>   	DC_DISABLE_DSC = 0x4,
>>   	DC_DISABLE_CLOCK_GATING = 0x8,
>>   	DC_DISABLE_PSR = 0x10,
>> +	DC_FORCE_SUBVP_MCLK_SWITCH = 0x20,
>>   };
>>   
>>   enum amd_dpm_forced_level;
>