Re: [PATCH v14 19/28] drm/connector: hdmi: Add RGB Quantization Range to the connector state

[Luc Ma <onion0709@xxxxxxxxx>]

Hi, 

On Tue, 21 May 2024 at 18:52, Maxime Ripard <mripard@xxxxxxxxxx> wrote:
>
> HDMI controller drivers will need to figure out the RGB range they need
> to configure based on a mode and property values. Let's expose that in
> the HDMI connector state so drivers can just use that value.
>
> Reviewed-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> Signed-off-by: Maxime Ripard <mripard@xxxxxxxxxx>
> ---
>  drivers/gpu/drm/display/drm_hdmi_state_helper.c | 29 +++++++++++++++++++++++++
>  drivers/gpu/drm/drm_atomic.c                    |  1 +
>  include/drm/drm_connector.h                     |  6 +++++
>  3 files changed, 36 insertions(+)
>
> diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
> index 888fe1fe9594..6d30c47fca65 100644
> --- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c
> +++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c
> @@ -49,10 +49,37 @@ connector_state_get_mode(const struct drm_connector_state *conn_state)
>                 return NULL;
>
>         return &crtc_state->mode;
>  }
>
> +static bool hdmi_is_limited_range(const struct drm_connector *connector,
> +                                 const struct drm_connector_state *conn_state)
> +{
> +       const struct drm_display_info *info = &connector->display_info;
> +       const struct drm_display_mode *mode =
> +               connector_state_get_mode(conn_state);
> +
> +       /*
> +        * The Broadcast RGB property only applies to RGB format, and
> +        * i915 just assumes limited range for YCbCr output, so let's
> +        * just do the same.
> +        */
> +       if (conn_state->hdmi.output_format != HDMI_COLORSPACE_RGB)
> +               return true;
> +
> +       if (conn_state->hdmi.broadcast_rgb == DRM_HDMI_BROADCAST_RGB_FULL)
> +               return false;
> +
> +       if (conn_state->hdmi.broadcast_rgb == DRM_HDMI_BROADCAST_RGB_LIMITED)
> +               return true;
> +
> +       if (!info->is_hdmi)
> +               return false;
> +
> +       return drm_default_rgb_quant_range(mode) == HDMI_QUANTIZATION_RANGE_LIMITED;
> +}
> +
>  static bool
>  sink_supports_format_bpc(const struct drm_connector *connector,
>                          const struct drm_display_info *info,
>                          const struct drm_display_mode *mode,
>                          unsigned int format, unsigned int bpc)
> @@ -315,10 +342,12 @@ int drm_atomic_helper_connector_hdmi_check(struct drm_connector *connector,
>                 drm_atomic_get_new_connector_state(state, connector);
>         const struct drm_display_mode *mode =
>                 connector_state_get_mode(new_conn_state);
>         int ret;
>
> +       new_conn_state->hdmi.is_limited_range = hdmi_is_limited_range(connector, new_conn_state);
> +
>         ret = hdmi_compute_config(connector, new_conn_state, mode);
>         if (ret)
>                 return ret;
>
>         if (old_conn_state->hdmi.broadcast_rgb != new_conn_state->hdmi.broadcast_rgb ||
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index 3e57d98d8418..07b4b394e3bf 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -1145,10 +1145,11 @@ static void drm_atomic_connector_print_state(struct drm_printer *p,
>
>         if (connector->connector_type == DRM_MODE_CONNECTOR_HDMIA ||
>             connector->connector_type == DRM_MODE_CONNECTOR_HDMIB) {
>                 drm_printf(p, "\tbroadcast_rgb=%s\n",
>                            drm_hdmi_connector_get_broadcast_rgb_name(state->hdmi.broadcast_rgb));
> +               drm_printf(p, "\tis_limited_range=%c\n", state->hdmi.is_limited_range ? 'y' : 'n');
>                 drm_printf(p, "\toutput_bpc=%u\n", state->hdmi.output_bpc);
>                 drm_printf(p, "\toutput_format=%s\n",
>                            drm_hdmi_connector_get_output_format_name(state->hdmi.output_format));
>                 drm_printf(p, "\ttmds_char_rate=%llu\n", state->hdmi.tmds_char_rate);
>         }
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index a40eaf3a8ce4..1fca26d51218 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -1068,10 +1068,16 @@ struct drm_connector_state {
>                  * @broadcast_rgb: Connector property to pass the
>                  * Broadcast RGB selection value.
>                  */
>                 enum drm_hdmi_broadcast_rgb broadcast_rgb;
>
> +               /**
> +                * @is_full_range: Is the output supposed to use a full

s/full/limited/g ?

> +                * RGB Quantization Range or not?
> +                */
> +               bool is_limited_range;
> +
>                 /**
>                  * @output_bpc: Bits per color channel to output.
>                  */
>                 unsigned int output_bpc;
>
>
> --
> 2.45.0
>


--
Luc