vGEM buffers are useful for passing data between software clients and
hardware renders. By allowing the user to create and attach fences to
the exported vGEM buffers (on the dma-buf), the user can implement a
deferred renderer and queue hardware operations like flipping and then
signal the buffer readiness (i.e. this allows the user to schedule
operations out-of-order, but have them complete in-order).
This also makes it much easier to write tightly controlled testcases for
dma-buf fencing and signaling between hardware drivers.
v2: Don't pretend the fences exist in an ordered timeline, but allocate
a separate fence-context for each fence so that the fences are
unordered.
v3: Make the debug output more interesting, and show the signaled status.
v4: Automatically signal the fence to prevent userspace from
indefinitely hanging drivers.
Testcase: igt/vgem_basic/dmabuf-fence
Testcase: igt/vgem_slow/nohang
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Zach Reizner <zachr@google.com>
Cc: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Zach Reizner <zachr@google.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1468571471-12610-1-git-send-email-chris@chris-wilson.co.uk
For actual sharing of buffers with other drivers (ie. actual hardware)
we'll need to pimp things out a bit better to deal w/ caching, multiple
memory domains, etc. See thread:
http://lists.freedesktop.org/archives/dri-devel/2015-May/083160.html
But for the llvmpipe use-case this isn't a problem. Nor do we really
need prime/dri3 (dri2 is sufficient). So until the other issues are
sorted lets remove DRIVER_PRIME.
v2: also drop the dead code
[airlied:
Okay I'm convinced this API could have a lot of use cases
that are really really bad, yes the upload use case is valid
however that isn't the only use case enabled, and if we allow
all the other use cases, people will start to (ab)use them,
and then they'll be ABI and my life will get worse, so disable
PRIME for now]
Acked-by: Thomas Hellstrom <thellstrom@vmware.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This patch implements the virtual GEM driver with PRIME sharing which
allows vgem to import a gem object from other drivers for the purpose
of mmap-ing them to userspace. The mmap is done using the mmap
operation exported by other drivers.
v2: remove platform_device and do not attach to dma bufs
v3: use drm helpers for get/put pages
v4: correct dumb create pitch
Reviewed-by: Rob Clark <robdclark@gmail.com> (v3)
Reviewed-by: Stéphane Marchesin <marcheu@chromium.org> (v3)
Signed-off-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Zach Reizner <zachr@google.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
