[PATCH v2 19/19] drm/msm/dp: allow YUV420 mode for DP connector when CDM available

[Abhinav Kumar]

On 2/10/2024 1:17 PM, Dmitry Baryshkov wrote:
> On Sat, 10 Feb 2024 at 21:19, Abhinav Kumar <quic_abhinavk at quicinc.com> wrote:
>>
>>
>>
>> On 2/10/2024 3:33 AM, Dmitry Baryshkov wrote:
>>> On Sat, 10 Feb 2024 at 03:52, Paloma Arellano <quic_parellan at quicinc.com> wrote:
>>>>
>>>> All the components of YUV420 over DP are added. Therefore, let's mark the
>>>> connector property as true for DP connector when the DP type is not eDP
>>>> and when there is a CDM block available.
>>>>
>>>> Changes in v2:
>>>>           - Check for if dp_catalog has a CDM block available instead of
>>>>             checking if VSC SDP is allowed when setting the dp connector's
>>>>             ycbcr_420_allowed parameter
>>>>
>>>> Signed-off-by: Paloma Arellano <quic_parellan at quicinc.com>
>>>> ---
>>>>    drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 4 +++-
>>>>    drivers/gpu/drm/msm/dp/dp_display.c     | 4 ++--
>>>>    drivers/gpu/drm/msm/dp/dp_drm.c         | 8 ++++++--
>>>>    drivers/gpu/drm/msm/dp/dp_drm.h         | 3 ++-
>>>>    drivers/gpu/drm/msm/msm_drv.h           | 5 +++--
>>>>    5 files changed, 16 insertions(+), 8 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>>>> index 723cc1d821431..beeaabe499abf 100644
>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>>>> @@ -565,6 +565,7 @@ static int _dpu_kms_initialize_displayport(struct drm_device *dev,
>>>>    {
>>>>           struct drm_encoder *encoder = NULL;
>>>>           struct msm_display_info info;
>>>> +       bool yuv_supported;
>>>>           int rc;
>>>>           int i;
>>>>
>>>> @@ -583,7 +584,8 @@ static int _dpu_kms_initialize_displayport(struct drm_device *dev,
>>>>                           return PTR_ERR(encoder);
>>>>                   }
>>>>
>>>> -               rc = msm_dp_modeset_init(priv->dp[i], dev, encoder);
>>>> +               yuv_supported = !!(dpu_kms->catalog->cdm);
>>>
>>> Drop parentheses please.
>>>
>>>> +               rc = msm_dp_modeset_init(priv->dp[i], dev, encoder, yuv_supported);
>>>>                   if (rc) {
>>>>                           DPU_ERROR("modeset_init failed for DP, rc = %d\n", rc);
>>>>                           return rc;
>>>> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
>>>> index ebcc76ef1d590..9b9f5f2921903 100644
>>>> --- a/drivers/gpu/drm/msm/dp/dp_display.c
>>>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
>>>> @@ -1471,7 +1471,7 @@ static int dp_display_get_next_bridge(struct msm_dp *dp)
>>>>    }
>>>>
>>>>    int msm_dp_modeset_init(struct msm_dp *dp_display, struct drm_device *dev,
>>>> -                       struct drm_encoder *encoder)
>>>> +                       struct drm_encoder *encoder, bool yuv_supported)
>>>>    {
>>>>           struct dp_display_private *dp_priv;
>>>>           int ret;
>>>> @@ -1487,7 +1487,7 @@ int msm_dp_modeset_init(struct msm_dp *dp_display, struct drm_device *dev,
>>>>                   return ret;
>>>>           }
>>>>
>>>> -       dp_display->connector = dp_drm_connector_init(dp_display, encoder);
>>>> +       dp_display->connector = dp_drm_connector_init(dp_display, encoder, yuv_supported);
>>>>           if (IS_ERR(dp_display->connector)) {
>>>>                   ret = PTR_ERR(dp_display->connector);
>>>>                   DRM_DEV_ERROR(dev->dev,
>>>> diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c
>>>> index 46e6889037e88..ab0d0d13b5e2c 100644
>>>> --- a/drivers/gpu/drm/msm/dp/dp_drm.c
>>>> +++ b/drivers/gpu/drm/msm/dp/dp_drm.c
>>>> @@ -353,7 +353,8 @@ int dp_bridge_init(struct msm_dp *dp_display, struct drm_device *dev,
>>>>    }
>>>>
>>>>    /* connector initialization */
>>>> -struct drm_connector *dp_drm_connector_init(struct msm_dp *dp_display, struct drm_encoder *encoder)
>>>> +struct drm_connector *dp_drm_connector_init(struct msm_dp *dp_display, struct drm_encoder *encoder,
>>>> +                                           bool yuv_supported)
>>>>    {
>>>>           struct drm_connector *connector = NULL;
>>>>
>>>> @@ -361,8 +362,11 @@ struct drm_connector *dp_drm_connector_init(struct msm_dp *dp_display, struct dr
>>>>           if (IS_ERR(connector))
>>>>                   return connector;
>>>>
>>>> -       if (!dp_display->is_edp)
>>>> +       if (!dp_display->is_edp) {
>>>>                   drm_connector_attach_dp_subconnector_property(connector);
>>>> +               if (yuv_supported)
>>>> +                       connector->ycbcr_420_allowed = true;
>>>
>>> Is there any reason to disallow YUV420 for eDP connectors?
>>>
>>>> +       }
>>>>
>>
>> Major reason was certainly validation but thinking about it more
>> closely, I need to check whether CDM over eDP is even possible.
>>
>> Historically, CDM could output only to HDMI OR WB using the bit we
>> program while setting up CDM and the same HDMI path is being used by DP
>> as well. But I need to check whether CDM can even output to eDP with the
>> same DP path. I dont have any documentation on this part yet.
> 
> I had the feeling that the DP / eDP difference on the chips is mostly
> on the PHY and software side. So I assumed that it should be possible
> to output YUV data to the eDP port in the same way as it is done for
> the DP port.
> 

This is true. I was not worried about DP / eDP controller but mostly 
whether eDP spec really allows YUV. From what I can read, it does.

So this check shall remain only because CDM has not been validated with eDP.

Do you need a TODO here and if we ever get a eDP panel which supports 
that, we can validate and relax this.