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[PATCH v7 02/11] drm/fourcc: Add DRM_FORMAT_XV15/XV20

Tomi Valkeinen posted 11 patches 2 months, 1 week ago
There is a newer version of this series
[PATCH v7 02/11] drm/fourcc: Add DRM_FORMAT_XV15/XV20
Posted by Tomi Valkeinen 2 months, 1 week ago 
Add two new pixel formats:

DRM_FORMAT_XV15 ("XV15")
DRM_FORMAT_XV20 ("XV20")

The formats are 2 plane 10 bit per component YCbCr, with the XV15 2x2
subsampled whereas XV20 is 2x1 subsampled.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Vishal Sagar <vishal.sagar@amd.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/drm_fourcc.c  | 6 ++++++
 include/uapi/drm/drm_fourcc.h | 8 ++++++++
 2 files changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
index e662aea9d105..b22ef86428a1 100644
--- a/drivers/gpu/drm/drm_fourcc.c
+++ b/drivers/gpu/drm/drm_fourcc.c
@@ -381,6 +381,12 @@ const struct drm_format_info *__drm_format_info(u32 format)
 		{ .format = DRM_FORMAT_S416,            .depth = 0,  .num_planes = 3,
 		  .char_per_block = { 2, 2, 2 }, .block_w = { 1, 1, 1 }, .block_h = { 1, 1, 1 },
 		  .hsub = 1, .vsub = 1, .is_yuv = true},
+		{ .format = DRM_FORMAT_XV15,		.depth = 0,  .num_planes = 2,
+		  .char_per_block = { 4, 8, 0 }, .block_w = { 3, 3, 0 }, .block_h = { 1, 1, 0 },
+		  .hsub = 2, .vsub = 2, .is_yuv = true },
+		{ .format = DRM_FORMAT_XV20,		.depth = 0,  .num_planes = 2,
+		  .char_per_block = { 4, 8, 0 }, .block_w = { 3, 3, 0 }, .block_h = { 1, 1, 0 },
+		  .hsub = 2, .vsub = 1, .is_yuv = true },
 	};
 
 	unsigned int i;
diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
index e527b24bd824..6c786701238e 100644
--- a/include/uapi/drm/drm_fourcc.h
+++ b/include/uapi/drm/drm_fourcc.h
@@ -322,6 +322,14 @@ extern "C" {
 #define DRM_FORMAT_RGB565_A8	fourcc_code('R', '5', 'A', '8')
 #define DRM_FORMAT_BGR565_A8	fourcc_code('B', '5', 'A', '8')
 
+/*
+ * 2 plane 10 bit per component YCrCb
+ * index 0 = Y plane, [31:0] x:Y2:Y1:Y0 2:10:10:10 little endian
+ * index 1 = Cb:Cr plane, [63:0] x:Cr2:Cb2:Cr1:x:Cb1:Cr0:Cb0 2:10:10:10:2:10:10:10 little endian
+ */
+#define DRM_FORMAT_XV15		fourcc_code('X', 'V', '1', '5') /* 2x2 subsampled Cr:Cb plane 2:10:10:10 */
+#define DRM_FORMAT_XV20		fourcc_code('X', 'V', '2', '0') /* 2x1 subsampled Cr:Cb plane 2:10:10:10 */
+
 /*
  * 2 plane YCbCr
  * index 0 = Y plane, [7:0] Y

-- 
2.43.0
Re: [PATCH v7 02/11] drm/fourcc: Add DRM_FORMAT_XV15/XV20
Posted by Laurent Pinchart 1 week, 5 days ago 
Hi Tomi,

On Mon, Dec 01, 2025 at 02:18:44PM +0200, Tomi Valkeinen wrote:
> Add two new pixel formats:
> 
> DRM_FORMAT_XV15 ("XV15")
> DRM_FORMAT_XV20 ("XV20")
> 
> The formats are 2 plane 10 bit per component YCbCr, with the XV15 2x2
> subsampled whereas XV20 is 2x1 subsampled.
> 
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Reviewed-by: Vishal Sagar <vishal.sagar@amd.com>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---
>  drivers/gpu/drm/drm_fourcc.c  | 6 ++++++
>  include/uapi/drm/drm_fourcc.h | 8 ++++++++
>  2 files changed, 14 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
> index e662aea9d105..b22ef86428a1 100644
> --- a/drivers/gpu/drm/drm_fourcc.c
> +++ b/drivers/gpu/drm/drm_fourcc.c
> @@ -381,6 +381,12 @@ const struct drm_format_info *__drm_format_info(u32 format)
>  		{ .format = DRM_FORMAT_S416,            .depth = 0,  .num_planes = 3,
>  		  .char_per_block = { 2, 2, 2 }, .block_w = { 1, 1, 1 }, .block_h = { 1, 1, 1 },
>  		  .hsub = 1, .vsub = 1, .is_yuv = true},
> +		{ .format = DRM_FORMAT_XV15,		.depth = 0,  .num_planes = 2,
> +		  .char_per_block = { 4, 8, 0 }, .block_w = { 3, 3, 0 }, .block_h = { 1, 1, 0 },
> +		  .hsub = 2, .vsub = 2, .is_yuv = true },

Given the horizontal subsampling, don't we have 6 pixels in 8 bytes ?

> +		{ .format = DRM_FORMAT_XV20,		.depth = 0,  .num_planes = 2,
> +		  .char_per_block = { 4, 8, 0 }, .block_w = { 3, 3, 0 }, .block_h = { 1, 1, 0 },
> +		  .hsub = 2, .vsub = 1, .is_yuv = true },
>  	};
>  
>  	unsigned int i;
> diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
> index e527b24bd824..6c786701238e 100644
> --- a/include/uapi/drm/drm_fourcc.h
> +++ b/include/uapi/drm/drm_fourcc.h
> @@ -322,6 +322,14 @@ extern "C" {
>  #define DRM_FORMAT_RGB565_A8	fourcc_code('R', '5', 'A', '8')
>  #define DRM_FORMAT_BGR565_A8	fourcc_code('B', '5', 'A', '8')
>  
> +/*
> + * 2 plane 10 bit per component YCrCb
> + * index 0 = Y plane, [31:0] x:Y2:Y1:Y0 2:10:10:10 little endian
> + * index 1 = Cb:Cr plane, [63:0] x:Cr2:Cb2:Cr1:x:Cb1:Cr0:Cb0 2:10:10:10:2:10:10:10 little endian
> + */
> +#define DRM_FORMAT_XV15		fourcc_code('X', 'V', '1', '5') /* 2x2 subsampled Cr:Cb plane 2:10:10:10 */
> +#define DRM_FORMAT_XV20		fourcc_code('X', 'V', '2', '0') /* 2x1 subsampled Cr:Cb plane 2:10:10:10 */
> +
>  /*
>   * 2 plane YCbCr
>   * index 0 = Y plane, [7:0] Y

-- 
Regards,

Laurent Pinchart
Re: [PATCH v7 02/11] drm/fourcc: Add DRM_FORMAT_XV15/XV20
Posted by Tomi Valkeinen 1 week, 4 days ago 
Hi,

On 28/01/2026 14:21, Laurent Pinchart wrote:
> Hi Tomi,
> 
> On Mon, Dec 01, 2025 at 02:18:44PM +0200, Tomi Valkeinen wrote:
>> Add two new pixel formats:
>>
>> DRM_FORMAT_XV15 ("XV15")
>> DRM_FORMAT_XV20 ("XV20")
>>
>> The formats are 2 plane 10 bit per component YCbCr, with the XV15 2x2
>> subsampled whereas XV20 is 2x1 subsampled.
>>
>> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>> Reviewed-by: Vishal Sagar <vishal.sagar@amd.com>
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>> ---
>>  drivers/gpu/drm/drm_fourcc.c  | 6 ++++++
>>  include/uapi/drm/drm_fourcc.h | 8 ++++++++
>>  2 files changed, 14 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
>> index e662aea9d105..b22ef86428a1 100644
>> --- a/drivers/gpu/drm/drm_fourcc.c
>> +++ b/drivers/gpu/drm/drm_fourcc.c
>> @@ -381,6 +381,12 @@ const struct drm_format_info *__drm_format_info(u32 format)
>>  		{ .format = DRM_FORMAT_S416,            .depth = 0,  .num_planes = 3,
>>  		  .char_per_block = { 2, 2, 2 }, .block_w = { 1, 1, 1 }, .block_h = { 1, 1, 1 },
>>  		  .hsub = 1, .vsub = 1, .is_yuv = true},
>> +		{ .format = DRM_FORMAT_XV15,		.depth = 0,  .num_planes = 2,
>> +		  .char_per_block = { 4, 8, 0 }, .block_w = { 3, 3, 0 }, .block_h = { 1, 1, 0 },
>> +		  .hsub = 2, .vsub = 2, .is_yuv = true },
> 
> Given the horizontal subsampling, don't we have 6 pixels in 8 bytes ?

No, the hsub is applied first.

If you look at framebuffer_check() and the called functions, the
calculations for the min_pitch for a 1920 wide XV15 buffer for the
second plane is:

width = frame_width / hsub
min_pitch = width * char_per_block[plane] / block_w[plane]

So:

width = 1920 / 2 = 960
min_pitch = 960 * 8 / 3 = 2560

 Tomi
Re: [PATCH v7 02/11] drm/fourcc: Add DRM_FORMAT_XV15/XV20
Posted by Laurent Pinchart 1 week, 4 days ago 
On Wed, Jan 28, 2026 at 03:53:21PM +0200, Tomi Valkeinen wrote:
> On 28/01/2026 14:21, Laurent Pinchart wrote:
> > On Mon, Dec 01, 2025 at 02:18:44PM +0200, Tomi Valkeinen wrote:
> >> Add two new pixel formats:
> >>
> >> DRM_FORMAT_XV15 ("XV15")
> >> DRM_FORMAT_XV20 ("XV20")
> >>
> >> The formats are 2 plane 10 bit per component YCbCr, with the XV15 2x2
> >> subsampled whereas XV20 is 2x1 subsampled.
> >>
> >> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> >> Reviewed-by: Vishal Sagar <vishal.sagar@amd.com>
> >> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> >> ---
> >>  drivers/gpu/drm/drm_fourcc.c  | 6 ++++++
> >>  include/uapi/drm/drm_fourcc.h | 8 ++++++++
> >>  2 files changed, 14 insertions(+)
> >>
> >> diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
> >> index e662aea9d105..b22ef86428a1 100644
> >> --- a/drivers/gpu/drm/drm_fourcc.c
> >> +++ b/drivers/gpu/drm/drm_fourcc.c
> >> @@ -381,6 +381,12 @@ const struct drm_format_info *__drm_format_info(u32 format)
> >>  		{ .format = DRM_FORMAT_S416,            .depth = 0,  .num_planes = 3,
> >>  		  .char_per_block = { 2, 2, 2 }, .block_w = { 1, 1, 1 }, .block_h = { 1, 1, 1 },
> >>  		  .hsub = 1, .vsub = 1, .is_yuv = true},
> >> +		{ .format = DRM_FORMAT_XV15,		.depth = 0,  .num_planes = 2,
> >> +		  .char_per_block = { 4, 8, 0 }, .block_w = { 3, 3, 0 }, .block_h = { 1, 1, 0 },
> >> +		  .hsub = 2, .vsub = 2, .is_yuv = true },
> > 
> > Given the horizontal subsampling, don't we have 6 pixels in 8 bytes ?
> 
> No, the hsub is applied first.
> 
> If you look at framebuffer_check() and the called functions, the
> calculations for the min_pitch for a 1920 wide XV15 buffer for the
> second plane is:
> 
> width = frame_width / hsub
> min_pitch = width * char_per_block[plane] / block_w[plane]
> 
> So:
> 
> width = 1920 / 2 = 960
> min_pitch = 960 * 8 / 3 = 2560

Indeed. I was looking at drm_format_info_min_pitch() and missed that it
was supposed to be called with the subsampled with. The argument is
documented as

 * @buffer_width: buffer width in pixels

which is quite ambiguous. The char_per_block documentation also does not
mention subsampling, adding to the confusion. This should be fixed, but
as far as this patch is concerned,

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

-- 
Regards,

Laurent Pinchart

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