Re: [PATCH 01/36] drm/fourcc: Add 2 plane YCbCr 10bit format support

[sandy.huang]

在 2019/9/24 上午2:30, Ville Syrjälä 写道:

On Mon, Sep 23, 2019 at 06:05:22AM -0700, sandy.huang wrote:

在 2019/9/23 上午5:53, Ville Syrjälä 写道:

On Mon, Sep 23, 2019 at 08:38:50PM +0800, Sandy Huang wrote:

diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
index 3feeaa3..5fe89e9 100644
--- a/include/uapi/drm/drm_fourcc.h
+++ b/include/uapi/drm/drm_fourcc.h
@@ -266,6 +266,21 @@ extern "C" {
   #define DRM_FORMAT_P016              fourcc_code('P', '0', '1', '6') /* 2x2 
subsampled Cr:Cb plane 16 bits per channel */

/*

+ * 2 plane YCbCr 10bit
+ * index 0 = Y plane, [9:0] Y
+ * index 1 = Cr:Cb plane, [19:0] Cr:Cb little endian
+ * or
+ * index 1 = Cb:Cr plane, [19:0] Cb:Cr little endian

What does "little endian" even mean for these?

It's Inherited from the following define, the difference is 8bit and 10bit.
/*
   * 2 plane YCbCr
   * index 0 = Y plane, [7:0] Y
   * index 1 = Cr:Cb plane, [15:0] Cr:Cb little endian
   * or
   * index 1 = Cb:Cr plane, [15:0] Cb:Cr little endian
   */
#define DRM_FORMAT_NV12        fourcc_code('N', 'V', '1', '2') /* 2x2
subsampled Cr:Cb plane */
#define DRM_FORMAT_NV21        fourcc_code('N', 'V', '2', '1') /* 2x2
subsampled Cb:Cr plane */
#define DRM_FORMAT_NV16        fourcc_code('N', 'V', '1', '6') /* 2x1
subsampled Cr:Cb plane */
#define DRM_FORMAT_NV61        fourcc_code('N', 'V', '6', '1') /* 2x1
subsampled Cb:Cr plane */
#define DRM_FORMAT_NV24        fourcc_code('N', 'V', '2', '4') /*
non-subsampled Cr:Cb plane */
#define DRM_FORMAT_NV42        fourcc_code('N', 'V', '4',

Something not aligned to bytes can't have its endianness defined the
same way as these. Just doesn't make sense.

Get it ,thanks.

+ */
+
+#define DRM_FORMAT_NV12_10     fourcc_code('N', 'A', '1', '2') /* 2x2 
subsampled Cr:Cb plane */
+#define DRM_FORMAT_NV21_10     fourcc_code('N', 'A', '2', '1') /* 2x2 
subsampled Cb:Cr plane */
+#define DRM_FORMAT_NV16_10     fourcc_code('N', 'A', '1', '6') /* 2x1 
subsampled Cr:Cb plane */
+#define DRM_FORMAT_NV61_10     fourcc_code('N', 'A', '6', '1') /* 2x1 
subsampled Cb:Cr plane */
+#define DRM_FORMAT_NV24_10     fourcc_code('N', 'A', '2', '4') /* 
non-subsampled Cr:Cb plane */
+#define DRM_FORMAT_NV42_10     fourcc_code('N', 'A', '4', '2') /* 
non-subsampled Cb:Cr plane */
+
+/*
    * 3 plane YCbCr
    * index 0: Y plane, [7:0] Y
    * index 1: Cb plane, [7:0] Cb
--
2.7.4



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