[Intel-gfx] [PATCH 3/4] drm/edid: Add drm_rgb_quant_range_selectable()

[Paulo Zanoni]

Hi

2013/1/16  <ville.syrjala at linux.intel.com>:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> drm_rgb_quant_range_selectable() will report whether the monitor
> claims to support for RGB quantization range selection.
>
> The information can be found in the CEA Video capability block.

Looks correct (checked against the spec, did not really test).

Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>

See below for optional bikeshedding:

>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/drm_edid.c |   33 +++++++++++++++++++++++++++++++++
>  include/drm/drm_crtc.h     |    1 +
>  2 files changed, 34 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 5a3770f..deba722 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -1483,9 +1483,11 @@ add_detailed_modes(struct drm_connector *connector, struct edid *edid,
>  #define VIDEO_BLOCK     0x02
>  #define VENDOR_BLOCK    0x03
>  #define SPEAKER_BLOCK  0x04
> +#define VIDEO_CAPABILITY_BLOCK 0x07
>  #define EDID_BASIC_AUDIO       (1 << 6)
>  #define EDID_CEA_YCRCB444      (1 << 5)
>  #define EDID_CEA_YCRCB422      (1 << 4)
> +#define EDID_CEA_VCDB_QS       (1 << 6)
>
>  /**
>   * Search EDID for CEA extension block.
> @@ -1902,6 +1904,37 @@ end:
>  EXPORT_SYMBOL(drm_detect_monitor_audio);
>
>  /**
> + * drm_rgb_quant_range_selectable - is RGB quantization range selectable?
> + *
> + * Check whether the monitor reports the RGB quantization range selection
> + * as supported. The AVI infoframe can then be used to inform the monitor
> + * which quantzation range (full or limited) is used.

s/quantzation/quantization/


> + */
> +bool drm_rgb_quant_range_selectable(struct edid *edid)
> +{
> +       u8 *edid_ext;
> +       int i, start, end;
> +
> +       edid_ext = drm_find_cea_extension(edid);
> +       if (!edid_ext)
> +               return false;
> +
> +       if (cea_db_offsets(edid_ext, &start, &end))
> +               return false;
> +
> +       for_each_cea_db(edid_ext, i, start, end) {
> +               if (cea_db_tag(&edid_ext[i]) == VIDEO_CAPABILITY_BLOCK &&
> +                   cea_db_payload_len(&edid_ext[i]) == 2) {
> +                       DRM_DEBUG_KMS("CEA VCDB 0x%02x\n", edid_ext[i + 2]);
> +                       return edid_ext[i + 2] & EDID_CEA_VCDB_QS;
> +               }
> +       }
> +
> +       return false;
> +}
> +EXPORT_SYMBOL(drm_rgb_quant_range_selectable);
> +
> +/**
>   * drm_add_display_info - pull display info out if present
>   * @edid: EDID data
>   * @info: display info (attached to connector)
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index 00d78b5..30892dc 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -1033,6 +1033,7 @@ extern u8 *drm_find_cea_extension(struct edid *edid);
>  extern u8 drm_match_cea_mode(struct drm_display_mode *to_match);
>  extern bool drm_detect_hdmi_monitor(struct edid *edid);
>  extern bool drm_detect_monitor_audio(struct edid *edid);
> +extern bool drm_rgb_quant_range_selectable(struct edid *edid);
>  extern int drm_mode_page_flip_ioctl(struct drm_device *dev,
>                                     void *data, struct drm_file *file_priv);
>  extern struct drm_display_mode *drm_cvt_mode(struct drm_device *dev,
> --
> 1.7.8.6
>
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-- 
Paulo Zanoni