On Tue, 01 Feb 2022 09:41:20 +0000 Simon Ser contact@emersion.fr wrote:
Follow-up for the DRM_IOCTL_MODE_GETFB2 docs.
v2: (Daniel Stone)
- Replace fourcc.org with drm_fourcc.h because this is the authoritative source and the website may have mismatches.
- Drop assumption that offsets will generally be 0.
- Mention that unused entries must be zero'ed out.
Signed-off-by: Simon Ser contact@emersion.fr Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch Cc: Pekka Paalanen pekka.paalanen@collabora.com Cc: Daniel Stone daniels@collabora.com
include/uapi/drm/drm_mode.h | 88 +++++++++++++++++++++++++------------ 1 file changed, 60 insertions(+), 28 deletions(-)
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h index e1e351682872..a345404dd315 100644 --- a/include/uapi/drm/drm_mode.h +++ b/include/uapi/drm/drm_mode.h @@ -663,41 +663,73 @@ struct drm_mode_fb_cmd { #define DRM_MODE_FB_INTERLACED (1<<0) /* for interlaced framebuffers */ #define DRM_MODE_FB_MODIFIERS (1<<1) /* enables ->modifer[] */
+/**
- struct drm_mode_fb_cmd2 - Frame-buffer metadata.
- This struct holds frame-buffer metadata. There are two ways to use it:
- User-space can fill this struct and perform a &DRM_IOCTL_MODE_ADDFB2
- ioctl to register a new frame-buffer. The new frame-buffer object ID will
- be set by the kernel in @fb_id.
- User-space can set @fb_id and perform a &DRM_IOCTL_MODE_GETFB2 ioctl to
- fetch metadata about an existing frame-buffer.
- In case of planar formats, this struct allows up to 4 buffer objects with
- offsets and pitches per plane. The pitch and offset order is dictated by the
- format FourCC as defined by ``drm_fourcc.h``, e.g. NV12 is described as:
YUV 4:2:0 image with a plane of 8 bit Y samples followed by an
interleaved U/V plane containing 8 bit 2x2 subsampled colour difference
samples.
- So it would consist of a Y plane at ``offsets[0]`` and a UV plane at
- ``offsets[1]``.
- To accommodate tiled, compressed, etc formats, a modifier can be specified.
- For more information see the "Format Modifiers" section. Note that even
- though it looks like we have a modifier per-plane, we in fact do not. The
- modifier for each plane must be identical. Thus all combinations of
- different data layouts for multi-plane formats must be enumerated as
- separate modifiers.
- All of the entries in @handles, @pitches, @offsets and @modifier must be
- zero when unused. Warning, for @offsets and @modifier zero can't be used to
- figure out whether the entry is used or not since it's a valid value (a zero
- offset is common, and a zero modifier is &DRM_FORMAT_MOD_LINEAR).
- */
struct drm_mode_fb_cmd2 {
- /** @fb_id: Object ID of the frame-buffer. */ __u32 fb_id;
- /** @width: Width of the frame-buffer. */ __u32 width;
- /** @height: Height of the frame-buffer. */ __u32 height;
- __u32 pixel_format; /* fourcc code from drm_fourcc.h */
- __u32 flags; /* see above flags */
- /**
* @pixel_format: FourCC format code, see ``DRM_FORMAT_*`` constants in* ``drm_fourcc.h``.*/- __u32 pixel_format;
- /**
* @flags: Frame-buffer flags (see &DRM_MODE_FB_INTERLACED and* &DRM_MODE_FB_MODIFIERS).*/- __u32 flags;
- /*
* In case of planar formats, this ioctl allows up to 4* buffer objects with offsets and pitches per plane.* The pitch and offset order is dictated by the fourcc,* e.g. NV12 (https://fourcc.org/yuv.php#NV12) is described as:** YUV 4:2:0 image with a plane of 8 bit Y samples* followed by an interleaved U/V plane containing* 8 bit 2x2 subsampled colour difference samples.** So it would consist of Y as offsets[0] and UV as* offsets[1]. Note that offsets[0] will generally* be 0 (but this is not required).** To accommodate tiled, compressed, etc formats, a* modifier can be specified. The default value of zero* indicates "native" format as specified by the fourcc.* Vendor specific modifier token. Note that even though* it looks like we have a modifier per-plane, we in fact* do not. The modifier for each plane must be identical.* Thus all combinations of different data layouts for* multi plane formats must be enumerated as separate* modifiers.
- /**
* @handles: GEM buffer handle, one per plane. Set to 0 if the plane is* unused.
Hi,
should there be a note that the handles may not be unique? I.e. one can use the same GEM buffer for more than one plane.
*/__u32 handles[4];
- __u32 pitches[4]; /* pitch for each plane */
- __u32 offsets[4]; /* offset of each plane */
- __u64 modifier[4]; /* ie, tiling, compress */
- /** @pitches: Pitch (aka. stride), one per plane. */
- __u32 pitches[4];
- /** @offsets: Offset into the buffer, one per plane. */
- __u32 offsets[4];
Would be nice to mention the units for pitches and offsets.
- /**
* @modifier: Format modifier, one per plane. See ``DRM_FORMAT_MOD_*``* constants in ``drm_fourcc.h``. All planes must use the same* modifier. Ignored unless &DRM_MODE_FB_MODIFIERS is set in @flags.*/- __u64 modifier[4];
};
#define DRM_MODE_FB_DIRTY_ANNOTATE_COPY 0x01
LGTM!
Acked-by: Pekka Paalanen pekka.paalanen@collabora.com
Thanks, pq