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

[Paloma Arellano <quic_parellan@xxxxxxxxxxx>]

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@xxxxxxxxxxx>
> > ---
> >   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