On 17.02.22 г. 14:46 ч., Tomi Valkeinen wrote:
Hi,
On 19/01/2022 12:23, Ivaylo Dimitrov wrote:
On devices with DMM, all allocations are done through either DMM or
TILER.
DMM/TILER being a limited resource means that such allocations will start
to fail before actual free memory is exhausted. What is even worse is
that
with time DMM/TILER space gets fragmented to the point that even if we
have
enough free DMM/TILER space and free memory, allocation fails because
there
is no big enough free block in DMM/TILER space.
Such failures can be easily observed with OMAP xorg DDX, for example -
starting few GUI applications (so buffers for their windows are
allocated)
and then rotating landscape<->portrait while closing and opening new
windows soon results in allocation failures.
Fix that by mapping buffers through DMM/TILER only when really needed,
like, for scanout buffers.
Doesn't this break users that get a buffer from omapdrm and expect it to
be contiguous?
If you mean dumb buffer, then no, this does not break users as dumb
buffers are allocated as scanout:
https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/omapdrm/omap_gem.c#L603
If you mean omap_bo allocated buffers, then if users want
linear(scanout) buffer, then they request it explicitly by passing
OMAP_BO_SCANOUT.
Ivo
