On Fri, Jan 12, 2018 at 02:21:16PM +0000, Ayan Halder wrote:
> drm_format_info does not describe the number of bits used for the alpha
> channel. That information is useful in a central place like drm_fourcc.c
> where it can be queried by the drivers that want to determine if 'alpha
> blending' is to be enabled or not.
>
> Signed-off-by: Ayan Kumar Halder <ayan.hal...@arm.com>
> Reviewed-by: Liviu Dudau <liviu.du...@arm.com>
> ---
> drivers/gpu/drm/drm_fourcc.c | 154
> ++++++++++++++++++++++++-------------------
> include/drm/drm_fourcc.h | 3 +
> 2 files changed, 89 insertions(+), 68 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
> index 9c0152d..073001b 100644
> --- a/drivers/gpu/drm/drm_fourcc.c
> +++ b/drivers/gpu/drm/drm_fourcc.c
<snip>
> @@ -348,3 +348,21 @@ int drm_format_plane_height(int height, uint32_t format,
> int plane)
> return height / info->vsub;
> }
> EXPORT_SYMBOL(drm_format_plane_height);
> +
> +/**
> + * drm_format_alpha_bits - get the number of bits per pixel
> + * representing alpha for format
> + * @format: pixel format (DRM_FORMAT_*)
> + *
> + * Returns:
> + * The number of bits per pixel representing alpha used by the
> + * specified pixel format.
> + */
> +int drm_format_alpha_bits(uint32_t format)
> +{
> + const struct drm_format_info *info;
> +
> + info = drm_format_info(format);
> + return info ? info->alpha : 0;
> +}
> +EXPORT_SYMBOL(drm_format_alpha_bits);
Do you have an actual use for this function somewhere?
> diff --git a/include/drm/drm_fourcc.h b/include/drm/drm_fourcc.h
> index 6942e84..5513510 100644
> --- a/include/drm/drm_fourcc.h
> +++ b/include/drm/drm_fourcc.h
> @@ -38,6 +38,7 @@ struct drm_mode_fb_cmd2;
> * @cpp: Number of bytes per pixel (per plane)
> * @hsub: Horizontal chroma subsampling factor
> * @vsub: Vertical chroma subsampling factor
> + * @alpha: Number of bits per pixel representing alpha
> */
> struct drm_format_info {
> u32 format;
> @@ -46,6 +47,7 @@ struct drm_format_info {
> u8 cpp[3];
> u8 hsub;
> u8 vsub;
> + u8 alpha;
> };
>
> /**
> @@ -57,6 +59,7 @@ struct drm_format_name_buf {
> };
>
> const struct drm_format_info *__drm_format_info(u32 format);
> +int drm_format_alpha_bits(u32 format);
> const struct drm_format_info *drm_format_info(u32 format);
> const struct drm_format_info *
> drm_get_format_info(struct drm_device *dev,
> --
> 2.7.4
>
> _______________________________________________
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> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Ville Syrjälä
Intel OTC
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