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

[Harry Wentland <harry.wentland@amd.com>]

On 1/5/23 15:12, Leo Li wrote:
> 
> 
> 
> 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.
>

Right, I was thinking of DSC but PSR-SU is eDP only.

Harry
 
> 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_ */
>>>
>>