[PATCH 05/17] drm/msm/dp: add an API to indicate if sink supports VSC SDP

[Paloma Arellano]

On 1/25/2024 1:23 PM, Dmitry Baryshkov wrote:
> On 25/01/2024 21:38, Paloma Arellano wrote:
>> 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.
>
> This API ideally should go to drm/display/drm_dp_helper.c
I'm not familiar how other vendors are checking if VSC SDP is supported. 
So in moving this API, I'm going to let the other vendors make the 
changes themselves.
>
>>
>> Signed-off-by: Paloma Arellano <quic_parellan at quicinc.com>
>> ---
>>   drivers/gpu/drm/msm/dp/dp_display.c |  3 ++-
>>   drivers/gpu/drm/msm/dp/dp_panel.c   | 35 +++++++++++++++++++++++++----
>>   drivers/gpu/drm/msm/dp/dp_panel.h   |  1 +
>>   3 files changed, 34 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c 
>> b/drivers/gpu/drm/msm/dp/dp_display.c
>> index ddac55f45a722..f6b3b6ca242f8 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_display.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
>> @@ -1617,7 +1617,8 @@ void dp_bridge_mode_set(struct drm_bridge 
>> *drm_bridge,
>>           !!(dp_display->dp_mode.drm_mode.flags & DRM_MODE_FLAG_NHSYNC);
>>         dp_display->dp_mode.out_fmt_is_yuv_420 =
>> - drm_mode_is_420_only(&dp->connector->display_info, adjusted_mode);
>> + drm_mode_is_420_only(&dp->connector->display_info, adjusted_mode) &&
>> +        dp_panel_vsc_sdp_supported(dp_display->panel);
>>         /* populate wide_bus_support to different layers */
>>       dp_display->ctrl->wide_bus_en =
>> diff --git a/drivers/gpu/drm/msm/dp/dp_panel.c 
>> b/drivers/gpu/drm/msm/dp/dp_panel.c
>> index 127f6af995cd1..af7820b6d35ec 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_panel.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_panel.c
>> @@ -17,6 +17,9 @@ struct dp_panel_private {
>>       struct dp_link *link;
>>       struct dp_catalog *catalog;
>>       bool panel_on;
>> +    bool vsc_supported;
>> +    u8 major;
>> +    u8 minor;
>>   };
>>     static void dp_panel_read_psr_cap(struct dp_panel_private *panel)
>> @@ -43,9 +46,10 @@ static void dp_panel_read_psr_cap(struct 
>> dp_panel_private *panel)
>>   static int dp_panel_read_dpcd(struct dp_panel *dp_panel)
>>   {
>>       int rc;
>> +    ssize_t rlen;
>>       struct dp_panel_private *panel;
>>       struct dp_link_info *link_info;
>> -    u8 *dpcd, major, minor;
>> +    u8 *dpcd, rx_feature;
>>         panel = container_of(dp_panel, struct dp_panel_private, 
>> dp_panel);
>>       dpcd = dp_panel->dpcd;
>> @@ -53,10 +57,19 @@ static int dp_panel_read_dpcd(struct dp_panel 
>> *dp_panel)
>>       if (rc)
>>           return rc;
>>   +    rlen = drm_dp_dpcd_read(panel->aux, 
>> DP_DPRX_FEATURE_ENUMERATION_LIST, &rx_feature, 1);
>> +    if (rlen != 1) {
>> +        panel->vsc_supported = false;
>> +        pr_debug("failed to read DP_DPRX_FEATURE_ENUMERATION_LIST\n");
>> +    } else {
>> +        panel->vsc_supported = !!(rx_feature & 
>> DP_VSC_SDP_EXT_FOR_COLORIMETRY_SUPPORTED);
>> +        pr_debug("vsc=%d\n", panel->vsc_supported);
>> +    }
>> +
>>       link_info = &dp_panel->link_info;
>>       link_info->revision = dpcd[DP_DPCD_REV];
>> -    major = (link_info->revision >> 4) & 0x0f;
>> -    minor = link_info->revision & 0x0f;
>> +    panel->major = (link_info->revision >> 4) & 0x0f;
>> +    panel->minor = link_info->revision & 0x0f;
>>         link_info->rate = drm_dp_max_link_rate(dpcd);
>>       link_info->num_lanes = drm_dp_max_lane_count(dpcd);
>> @@ -69,7 +82,7 @@ static int dp_panel_read_dpcd(struct dp_panel 
>> *dp_panel)
>>       if (link_info->rate > dp_panel->max_dp_link_rate)
>>           link_info->rate = dp_panel->max_dp_link_rate;
>>   -    drm_dbg_dp(panel->drm_dev, "version: %d.%d\n", major, minor);
>> +    drm_dbg_dp(panel->drm_dev, "version: %d.%d\n", panel->major, 
>> panel->minor);
>>       drm_dbg_dp(panel->drm_dev, "link_rate=%d\n", link_info->rate);
>>       drm_dbg_dp(panel->drm_dev, "lane_count=%d\n", 
>> link_info->num_lanes);
>>   @@ -280,6 +293,20 @@ void dp_panel_tpg_config(struct dp_panel 
>> *dp_panel, bool enable)
>>       dp_catalog_panel_tpg_enable(catalog, 
>> &panel->dp_panel.dp_mode.drm_mode);
>>   }
>>   +bool dp_panel_vsc_sdp_supported(struct dp_panel *dp_panel)
>> +{
>> +    struct dp_panel_private *panel;
>> +
>> +    if (!dp_panel) {
>> +        pr_err("invalid input\n");
>> +        return false;
>> +    }
>> +
>> +    panel = container_of(dp_panel, struct dp_panel_private, dp_panel);
>> +
>> +    return panel->major >= 1 && panel->minor >= 3 && 
>> panel->vsc_supported;
>> +}
>> +
>>   void dp_panel_dump_regs(struct dp_panel *dp_panel)
>>   {
>>       struct dp_catalog *catalog;
>> diff --git a/drivers/gpu/drm/msm/dp/dp_panel.h 
>> b/drivers/gpu/drm/msm/dp/dp_panel.h
>> index 6ec68be9f2366..590eca5ce304b 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_panel.h
>> +++ b/drivers/gpu/drm/msm/dp/dp_panel.h
>> @@ -66,6 +66,7 @@ int dp_panel_get_modes(struct dp_panel *dp_panel,
>>           struct drm_connector *connector);
>>   void dp_panel_handle_sink_request(struct dp_panel *dp_panel);
>>   void dp_panel_tpg_config(struct dp_panel *dp_panel, bool enable);
>> +bool dp_panel_vsc_sdp_supported(struct dp_panel *dp_panel);
>>     /**
>>    * is_link_rate_valid() - validates the link rate
>