Format modifiers are for the buffer layout only, not for the allocation
parameters, placement, etc. See the doc comment at the top of
drm_fourcc.h.
On 11/29/22 18:18, Simon Ser wrote:
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> Format modifiers are for the buffer layout only, not for the allocation
> parameters, placement, etc. See the doc comment at the top of
> drm_fourcc.h.
In the v4l2 mail list, we have such proposal that dropping the pixel
formats(not the codec formats) from v4l2 header completely, as the
growing of tile pixel formats.
But we can't get rid of those variants about non-contiguous(the same
value FOURCC in v4l2 are all for the contiguous memory).
Before I solve this problem, I believe the support for tile formats in
v4l2 would never be stable.
The most common way here is to hack the pixel format modifier, then
userspace library could be aware this in allocation and get properties
of the drm_planes.
Or another way, we could add a common plane property, indicated that
whether the driver requests contiguous memory plane for a format?
--
Hsia-Jun(Randy) Li