[PATCH v5 04/17] drm: add helper to validate ycbcr420 modes

[Ville Syrjälä]

On Tue, Jul 04, 2017 at 07:41:51PM +0530, Shashank Sharma wrote:
> YCBCR420 modes are supported only on HDMI 2.0 capable sources.
> This patch adds a drm helper to validate YCBCR420-only mode
> on a particular connector. This function will help pruning
> the YCBCR420-only modes from the connector's modelist.
> 
> V5: Introduced the patch in series.
> 
> Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
> Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
> ---
>  drivers/gpu/drm/drm_edid.c         |  3 ++-
>  drivers/gpu/drm/drm_modes.c        | 28 ++++++++++++++++++++++++++++
>  drivers/gpu/drm/drm_probe_helper.c |  4 ++++
>  include/drm/drm_edid.h             |  1 +
>  include/drm/drm_modes.h            |  5 +++++
>  5 files changed, 40 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index b879662..ad26c5e 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -2947,10 +2947,11 @@ u8 drm_match_cea_mode(const struct drm_display_mode *to_match)
>  }
>  EXPORT_SYMBOL(drm_match_cea_mode);
>  
> -static bool drm_valid_cea_vic(u8 vic)
> +bool drm_valid_cea_vic(u8 vic)
>  {
>  	return vic > 0 && vic < ARRAY_SIZE(edid_cea_modes);
>  }
> +EXPORT_SYMBOL(drm_valid_cea_vic);
>  
>  /**
>   * drm_get_cea_aspect_ratio - get the picture aspect ratio corresponding to
> diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
> index f2493b9..3b53c8e3 100644
> --- a/drivers/gpu/drm/drm_modes.c
> +++ b/drivers/gpu/drm/drm_modes.c
> @@ -1083,6 +1083,34 @@ drm_mode_validate_size(const struct drm_display_mode *mode,
>  }
>  EXPORT_SYMBOL(drm_mode_validate_size);
>  
> +/**
> + * drm_mode_ycbcr420_only - add 'ycbcr420-only' modes only when allowed
> + * @mode: mode to check
> + * @connector: drm connector under action
> + *
> + * This function is a helper which can be used to filter out any YCBCR420
> + * only mode, when the source doesn't support it.
> + *
> + * Returns:
> + * The mode status
> + */
> +enum drm_mode_status
> +drm_mode_validate_ycbcr420(const struct drm_display_mode *mode,
> +			   struct drm_connector *connector)
> +{
> +	u8 vic = drm_match_cea_mode(mode);
> +	enum drm_mode_status status = MODE_OK;
> +	struct drm_hdmi_info *hdmi = &connector->display_info.hdmi;
> +
> +	if (drm_valid_cea_vic(vic) && test_bit(vic, hdmi->y420_vdb_modes)) {

The drm_valid_cea_vic() check seems redundant to me.
Why do you think we need it?

Also I don't think this will compile since we don't have
y420_vdb_modes[] yet.

> +		if (!connector->ycbcr_420_allowed)
> +			status = MODE_NO_420;
> +	}
> +
> +	return status;
> +}
> +EXPORT_SYMBOL(drm_mode_validate_ycbcr420);
> +
>  #define MODE_STATUS(status) [MODE_ ## status + 3] = #status
>  
>  static const char * const drm_mode_status_names[] = {
> diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
> index 00e6832..904966c 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -528,6 +528,10 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
>  		if (mode->status == MODE_OK)
>  			mode->status = drm_mode_validate_pipeline(mode,
>  								  connector);
> +
> +		if (mode->status == MODE_OK)
> +			mode->status = drm_mode_validate_ycbcr420(mode,
> +								  connector);
>  	}
>  
>  prune:
> diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
> index 89c0062..b55b2a7 100644
> --- a/include/drm/drm_edid.h
> +++ b/include/drm/drm_edid.h
> @@ -477,4 +477,5 @@ void drm_edid_get_monitor_name(struct edid *edid, char *name,
>  struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev,
>  					   int hsize, int vsize, int fresh,
>  					   bool rb);
> +bool drm_valid_cea_vic(u8 vic);
>  #endif /* __DRM_EDID_H__ */
> diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h
> index 94ac771..f8a1268 100644
> --- a/include/drm/drm_modes.h
> +++ b/include/drm/drm_modes.h
> @@ -80,6 +80,7 @@ struct videomode;
>   * @MODE_ONE_SIZE: only one resolution is supported
>   * @MODE_NO_REDUCED: monitor doesn't accept reduced blanking
>   * @MODE_NO_STEREO: stereo modes not supported
> + * @MODE_NO_420: ycbcr 420 modes not supported
>   * @MODE_STALE: mode has become stale
>   * @MODE_BAD: unspecified reason
>   * @MODE_ERROR: error condition
> @@ -124,6 +125,7 @@ enum drm_mode_status {
>  	MODE_ONE_SIZE,
>  	MODE_NO_REDUCED,
>  	MODE_NO_STEREO,
> +	MODE_NO_420,
>  	MODE_STALE = -3,
>  	MODE_BAD = -2,
>  	MODE_ERROR = -1
> @@ -496,6 +498,9 @@ bool drm_mode_equal_no_clocks_no_stereo(const struct drm_display_mode *mode1,
>  enum drm_mode_status drm_mode_validate_basic(const struct drm_display_mode *mode);
>  enum drm_mode_status drm_mode_validate_size(const struct drm_display_mode *mode,
>  					    int maxX, int maxY);
> +enum drm_mode_status
> +drm_mode_validate_ycbcr420(const struct drm_display_mode *mode,
> +			   struct drm_connector *connector);
>  void drm_mode_prune_invalid(struct drm_device *dev,
>  			    struct list_head *mode_list, bool verbose);
>  void drm_mode_sort(struct list_head *mode_list);
> -- 
> 2.7.4

-- 
Ville Syrjälä
Intel OTC