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| author | Simon Ser <contact@emersion.fr> | 2023-08-21 13:15:56 +0000 |
|---|---|---|
| committer | Simon Ser <contact@emersion.fr> | 2023-10-25 17:32:56 +0200 |
| commit | b8644c4ae2b646b89b40892bf93cbb6f7451c868 (patch) | |
| tree | 980ee94e4049e2c79df5f29e522c5aa36fec3979 /include/uapi/drm/drm.h | |
| parent | d4b384228562848e4b76b608a5876c92160e993c (diff) | |
| download | linux-b8644c4ae2b646b89b40892bf93cbb6f7451c868.tar.gz linux-b8644c4ae2b646b89b40892bf93cbb6f7451c868.tar.bz2 linux-b8644c4ae2b646b89b40892bf93cbb6f7451c868.zip | |
drm/doc: document DRM_IOCTL_MODE_CREATE_DUMB
The main motivation is to repeat that dumb buffers should not be
abused for anything else than basic software rendering with KMS.
User-space devs are more likely to look at the IOCTL docs than to
actively search for the driver-oriented "Dumb Buffer Objects"
section.
v2: reference DRM_CAP_DUMB_BUFFER, DRM_CAP_DUMB_PREFERRED_DEPTH and
DRM_CAP_DUMB_PREFER_SHADOW (Pekka)
Signed-off-by: Simon Ser <contact@emersion.fr>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230821131548.269204-1-contact@emersion.fr
Diffstat (limited to 'include/uapi/drm/drm.h')
| -rw-r--r-- | include/uapi/drm/drm.h | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h index 794c1d857677..de723566c5ae 100644 --- a/include/uapi/drm/drm.h +++ b/include/uapi/drm/drm.h @@ -1134,6 +1134,26 @@ extern "C" { #define DRM_IOCTL_MODE_PAGE_FLIP DRM_IOWR(0xB0, struct drm_mode_crtc_page_flip) #define DRM_IOCTL_MODE_DIRTYFB DRM_IOWR(0xB1, struct drm_mode_fb_dirty_cmd) +/** + * DRM_IOCTL_MODE_CREATE_DUMB - Create a new dumb buffer object. + * + * KMS dumb buffers provide a very primitive way to allocate a buffer object + * suitable for scanout and map it for software rendering. KMS dumb buffers are + * not suitable for hardware-accelerated rendering nor video decoding. KMS dumb + * buffers are not suitable to be displayed on any other device than the KMS + * device where they were allocated from. Also see + * :ref:`kms_dumb_buffer_objects`. + * + * The IOCTL argument is a struct drm_mode_create_dumb. + * + * User-space is expected to create a KMS dumb buffer via this IOCTL, then add + * it as a KMS framebuffer via &DRM_IOCTL_MODE_ADDFB and map it via + * &DRM_IOCTL_MODE_MAP_DUMB. + * + * &DRM_CAP_DUMB_BUFFER indicates whether this IOCTL is supported. + * &DRM_CAP_DUMB_PREFERRED_DEPTH and &DRM_CAP_DUMB_PREFER_SHADOW indicate + * driver preferences for dumb buffers. + */ #define DRM_IOCTL_MODE_CREATE_DUMB DRM_IOWR(0xB2, struct drm_mode_create_dumb) #define DRM_IOCTL_MODE_MAP_DUMB DRM_IOWR(0xB3, struct drm_mode_map_dumb) #define DRM_IOCTL_MODE_DESTROY_DUMB DRM_IOWR(0xB4, struct drm_mode_destroy_dumb) |