[PATCH v5] drm/dp: add an API to indicate if sink supports VSC SDP

[Abhinav Kumar]

Hi DRM maintainers

Gentle ping for reviews on this one.

Since the dependent series is mostly complete, would like to get your 
reviews on this one to land it.

Thanks

Abhinav

On 2/15/2024 11:15 AM, Abhinav Kumar wrote:
> From: Paloma Arellano <quic_parellan at quicinc.com>
> 
> YUV420 format is supported only in the VSC SDP packet and not through
> MSA. Hence add an API which indicates the sink support which can be used
> by the rest of the DP programming.
> 
> changes in v5:
> 	- rebased on top of drm-tip
> 
> changes in v4:
> 	- bail out early if dpcd rev check fails
> 
> changes in v3:
> 	- fix the commit title prefix to drm/dp
> 	- get rid of redundant !!
> 	- break out this change from series [1] to get acks from drm core
> 	  maintainers
> 
> Changes in v2:
> 	- Move VSC SDP support check API from dp_panel.c to
> 	  drm_dp_helper.c
> 
> [1]: https://patchwork.freedesktop.org/series/129180/
> 
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> Signed-off-by: Paloma Arellano <quic_parellan at quicinc.com>
> Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
> ---
>   drivers/gpu/drm/display/drm_dp_helper.c | 23 +++++++++++++++++++++++
>   include/drm/display/drm_dp_helper.h     |  2 ++
>   2 files changed, 25 insertions(+)
> 
> diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
> index 8d6ce46471ae..61b11cb45245 100644
> --- a/drivers/gpu/drm/display/drm_dp_helper.c
> +++ b/drivers/gpu/drm/display/drm_dp_helper.c
> @@ -2913,6 +2913,29 @@ void drm_dp_vsc_sdp_log(struct drm_printer *p, const struct drm_dp_vsc_sdp *vsc)
>   }
>   EXPORT_SYMBOL(drm_dp_vsc_sdp_log);
>   
> +/**
> + * drm_dp_vsc_sdp_supported() - check if vsc sdp is supported
> + * @aux: DisplayPort AUX channel
> + * @dpcd: DisplayPort configuration data
> + *
> + * Returns true if vsc sdp is supported, else returns false
> + */
> +bool drm_dp_vsc_sdp_supported(struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE])
> +{
> +	u8 rx_feature;
> +
> +	if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_13)
> +		return false;
> +
> +	if (drm_dp_dpcd_readb(aux, DP_DPRX_FEATURE_ENUMERATION_LIST, &rx_feature) != 1) {
> +		drm_dbg_dp(aux->drm_dev, "failed to read DP_DPRX_FEATURE_ENUMERATION_LIST\n");
> +		return false;
> +	}
> +
> +	return (rx_feature & DP_VSC_SDP_EXT_FOR_COLORIMETRY_SUPPORTED);
> +}
> +EXPORT_SYMBOL(drm_dp_vsc_sdp_supported);
> +
>   /**
>    * drm_dp_get_pcon_max_frl_bw() - maximum frl supported by PCON
>    * @dpcd: DisplayPort configuration data
> diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h
> index d02014a87f12..36351f3cdba9 100644
> --- a/include/drm/display/drm_dp_helper.h
> +++ b/include/drm/display/drm_dp_helper.h
> @@ -100,6 +100,8 @@ struct drm_dp_vsc_sdp {
>   
>   void drm_dp_vsc_sdp_log(struct drm_printer *p, const struct drm_dp_vsc_sdp *vsc);
>   
> +bool drm_dp_vsc_sdp_supported(struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE]);
> +
>   int drm_dp_psr_setup_time(const u8 psr_cap[EDP_PSR_RECEIVER_CAP_SIZE]);
>   
>   static inline int