Re: [PATCH v2] drm/amd/display: fix PSR-SU/DSC interoperability support

[Leo Li <sunpeng.li@amd.com>]

On 1/5/23 15:07, Hamza Mahfooz wrote:
> On 1/5/23 13:29, Harry Wentland wrote:
>>
>>
>> On 1/5/23 12:38, Hamza Mahfooz wrote:
>>> Currently, there are issues with enabling PSR-SU + DSC. This stems from
>>> the fact that DSC imposes a slice height on transmitted video data and
>>> we are not conforming to that slice height in PSR-SU regions. So, pass
>>> slice_height into su_y_granularity to feed the DSC slice height into
>>> PSR-SU code.
>>>
>>> Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
>>> ---
>>> v2: move code to modules/power.
>>> ---
>>>   .../drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c |  3 ++
>>>   .../amd/display/modules/power/power_helpers.c | 35 +++++++++++++++++++
>>>   .../amd/display/modules/power/power_helpers.h |  3 ++
>>>   3 files changed, 41 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c 
>>> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c
>>> index 26291db0a3cf..872d06fe1436 100644
>>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c
>>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c
>>> @@ -122,6 +122,9 @@ bool amdgpu_dm_link_setup_psr(struct 
>>> dc_stream_state *stream)
>>>           psr_config.allow_multi_disp_optimizations =
>>>               (amdgpu_dc_feature_mask & DC_PSR_ALLOW_MULTI_DISP_OPT);
>>> +        if (!psr_su_set_y_granularity(dc, link, stream, &psr_config))
>>> +            return false;
>>> +
>>>           ret = dc_link_setup_psr(link, stream, &psr_config, 
>>> &psr_context);
>>>       }
>>> diff --git 
>>> a/drivers/gpu/drm/amd/display/modules/power/power_helpers.c 
>>> b/drivers/gpu/drm/amd/display/modules/power/power_helpers.c
>>> index 9b5d9b2c9a6a..4d27ad9f7370 100644
>>> --- a/drivers/gpu/drm/amd/display/modules/power/power_helpers.c
>>> +++ b/drivers/gpu/drm/amd/display/modules/power/power_helpers.c
>>> @@ -916,3 +916,38 @@ bool mod_power_only_edp(const struct dc_state 
>>> *context, const struct dc_stream_s
>>>   {
>>>       return context && context->stream_count == 1 && 
>>> dc_is_embedded_signal(stream->signal);
>>>   }
>>> +
>>> +bool psr_su_set_y_granularity(struct dc *dc, struct dc_link *link,
>>> +                  struct dc_stream_state *stream,
>>> +                  struct psr_config *config)
>>> +{
>>> +    uint16_t pic_height;
>>> +    uint8_t slice_height;
>>> +
>>> +    if (!dc->caps.edp_dsc_support ||
>>> +        link->panel_config.dsc.disable_dsc_edp ||
>>> +        
>>> !link->dpcd_caps.dsc_caps.dsc_basic_caps.fields.dsc_support.DSC_SUPPORT ||
>>> +        !stream->timing.dsc_cfg.num_slices_v)
>>
>> I'm not sure this condition is correct. We can have DSC but not eDP DSC
>> support.
>>
> 
> AFAIK PSR-SU displays use eDP exclusively, so we shouldn't have to worry 
> about this case.

Right, the dc_link here should only be eDP. I suppose that isn't quite
clear.

Maybe add this as part of the condition?

if (!(link->connector_signal & SIGNAL_TYPE_EDP))
     return true;

Thanks,
Leo

> 
>>> +        return true;
>>> +
>>> +    pic_height = stream->timing.v_addressable +
>>> +        stream->timing.v_border_top + stream->timing.v_border_bottom;
>>> +    slice_height = pic_height / stream->timing.dsc_cfg.num_slices_v;
>>> +
>>> +    if (slice_height) {
>>> +        if (config->su_y_granularity &&
>>> +            (slice_height % config->su_y_granularity)) {
>>> +            WARN(1,
>>
>> We don't use WARN in display/dc or display/modules. DC_LOG_WARNING
>> might be better, or log it in the caller.
>>
>> Harry
>>
>>> +                 "%s: dsc: %d, slice_height: %d, num_slices_v: %d\n",
>>> +                 __func__,
>>> +                 stream->sink->dsc_caps.dsc_dec_caps.is_dsc_supported,
>>> +                 slice_height,
>>> +                 stream->timing.dsc_cfg.num_slices_v);
>>> +            return false;
>>> +        }
>>> +
>>> +        config->su_y_granularity = slice_height;
>>> +    }
>>> +
>>> +    return true;
>>> +}
>>> diff --git 
>>> a/drivers/gpu/drm/amd/display/modules/power/power_helpers.h 
>>> b/drivers/gpu/drm/amd/display/modules/power/power_helpers.h
>>> index 316452e9dbc9..bb16b37b83da 100644
>>> --- a/drivers/gpu/drm/amd/display/modules/power/power_helpers.h
>>> +++ b/drivers/gpu/drm/amd/display/modules/power/power_helpers.h
>>> @@ -59,4 +59,7 @@ void mod_power_calc_psr_configs(struct psr_config 
>>> *psr_config,
>>>           const struct dc_stream_state *stream);
>>>   bool mod_power_only_edp(const struct dc_state *context,
>>>           const struct dc_stream_state *stream);
>>> +bool psr_su_set_y_granularity(struct dc *dc, struct dc_link *link,
>>> +                  struct dc_stream_state *stream,
>>> +                  struct psr_config *config);
>>>   #endif /* MODULES_POWER_POWER_HELPERS_H_ */
>>
>