在 2026-02-25三的 08:26 +0100，Thomas Zimmermann写道： > Hi, > > Am 25.02.26 um 07:13 schrieb Icenowy Zheng: > > The ioctl interfaces for dumb buffers currently only properly > > support > > linear buffers. > > > > Mention this in the documentation snippet of dumb-buffers source > > code, > > which is referenced by drm-kms.rst and will end up in the built > > kernel > > documentation. > > > > Also mention the existence of current drivers abusing dumb buffers > > for > > AFBC to reduce confusion about this. > > > > Signed-off-by: Icenowy Zheng <[email protected]> > > --- > > drivers/gpu/drm/drm_dumb_buffers.c | 7 ++++++- > > We documented the meaning of the color bits and the behavior of the > dumb-buffer interface at [1]. If anything is missing, it should be > added > there.
Yes, I saw this piece of document; however it's part of the interface document instead of a concept document, and the whole existence of the document snippet I am changing can be considered a duplicate of the interface document. Thanks Icenowy > > Best regards > Thomas > > [1] > https://elixir.bootlin.com/linux/v6.19/source/include/uapi/drm/drm_mode.h#L1200 > > > 1 file changed, 6 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/drm_dumb_buffers.c > > b/drivers/gpu/drm/drm_dumb_buffers.c > > index e2b62e5fb891b..06f74460adf62 100644 > > --- a/drivers/gpu/drm/drm_dumb_buffers.c > > +++ b/drivers/gpu/drm/drm_dumb_buffers.c > > @@ -57,7 +57,12 @@ > > * > > * Note that dumb objects may not be used for gpu acceleration, > > as has been > > * attempted on some ARM embedded platforms. Such drivers really > > must have > > - * a hardware-specific ioctl to allocate suitable buffer objects. > > + * a hardware-specific ioctl to allocate suitable buffer objects. > > They are > > + * also currently meant for only linear buffers, and using them > > with any > > + * modifier other than DRM_FORMAT_MOD_LINEAR is undefined > > behavior. There > > + * exist some KMS drivers abusing dumb objects for AFBC > > framebuffers, but this > > + * behavior is discouraged, only exists as a hack now and > > shouldn't be > > + * replicated. > > */ > > > > static int drm_mode_align_dumb(struct drm_mode_create_dumb *args,
