[PATCH] drm: fix pixel size of NV12 / NV16 pixel formats

[PATCH] drm: fix pixel size of NV12 / NV16 pixel formats

[Fabien Dessenne]

With NV12, NV21, NV16 and NV61 formats, the size of one pixel from the
UV plane (plane #1) is one byte.

Indeed, these pixel formats use 4:2:x chroma subsampling: the chroma
pixels are sampled at half the luma: for 2 pixels, there are 1 Cb +
1 Cr = 2 bytes.
So for plane #1, the correct size is actually 1 byte per pixel.

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
---
 drivers/gpu/drm/drm_crtc.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 3313f7e..572c6fa 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -5618,10 +5618,6 @@ int drm_format_plane_cpp(uint32_t format, int plane)
 	case DRM_FORMAT_UYVY:
 	case DRM_FORMAT_VYUY:
 		return 2;
-	case DRM_FORMAT_NV12:
-	case DRM_FORMAT_NV21:
-	case DRM_FORMAT_NV16:
-	case DRM_FORMAT_NV61:
 	case DRM_FORMAT_NV24:
 	case DRM_FORMAT_NV42:
 		return plane ? 2 : 1;
@@ -5635,6 +5631,10 @@ int drm_format_plane_cpp(uint32_t format, int plane)
 	case DRM_FORMAT_YVU422:
 	case DRM_FORMAT_YUV444:
 	case DRM_FORMAT_YVU444:
+	case DRM_FORMAT_NV12:
+	case DRM_FORMAT_NV21:
+	case DRM_FORMAT_NV16:
+	case DRM_FORMAT_NV61:
 		return 1;
 	default:
 		drm_fb_get_bpp_depth(format, &depth, &bpp);
-- 
1.9.1

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Re: [PATCH] drm: fix pixel size of NV12 / NV16 pixel formats

[Ville Syrjälä]

On Thu, Apr 28, 2016 at 10:40:39AM +0200, Fabien Dessenne wrote:
> With NV12, NV21, NV16 and NV61 formats, the size of one pixel from the
> UV plane (plane #1) is one byte.
> 
> Indeed, these pixel formats use 4:2:x chroma subsampling: the chroma
> pixels are sampled at half the luma: for 2 pixels, there are 1 Cb +
> 1 Cr = 2 bytes.

You just said it, it's 2 bytes. NAK

> So for plane #1, the correct size is actually 1 byte per pixel.
> 
> Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
> ---
>  drivers/gpu/drm/drm_crtc.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index 3313f7e..572c6fa 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -5618,10 +5618,6 @@ int drm_format_plane_cpp(uint32_t format, int plane)
>  	case DRM_FORMAT_UYVY:
>  	case DRM_FORMAT_VYUY:
>  		return 2;
> -	case DRM_FORMAT_NV12:
> -	case DRM_FORMAT_NV21:
> -	case DRM_FORMAT_NV16:
> -	case DRM_FORMAT_NV61:
>  	case DRM_FORMAT_NV24:
>  	case DRM_FORMAT_NV42:
>  		return plane ? 2 : 1;
> @@ -5635,6 +5631,10 @@ int drm_format_plane_cpp(uint32_t format, int plane)
>  	case DRM_FORMAT_YVU422:
>  	case DRM_FORMAT_YUV444:
>  	case DRM_FORMAT_YVU444:
> +	case DRM_FORMAT_NV12:
> +	case DRM_FORMAT_NV21:
> +	case DRM_FORMAT_NV16:
> +	case DRM_FORMAT_NV61:
>  		return 1;
>  	default:
>  		drm_fb_get_bpp_depth(format, &depth, &bpp);
> -- 
> 1.9.1
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Ville Syrjälä
Intel OTC
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