[Mesa-dev] [PATCH v2 1/2] egl/wayland: Check queryImage return for wl_buffer

Daniel Stone daniel at fooishbar.org
Wed Oct 4 10:48:50 UTC 2017

Hi Marek,

On 3 October 2017 at 17:00, Marek Olšák <maraeo at gmail.com> wrote:
> On Mon, Oct 2, 2017 at 8:09 PM, Daniel Stone <daniel at fooishbar.org> wrote:
>> Perhaps unsurprisingly, adding __DRI_IMAGE_USE_SCANOUT to
>> src/egl/drivers/dri2/platform_wayland.c in the createImage() fallback
>> path (i.e. not createImageWithModifiers) fixes things. That being
>> said, Weston does do the GBM BO import with the scanout flag, which
>> will call the DRIImage's validateUsage() hook with the SCANOUT bit
>> set; for now, it should be enough to just detect that the image is not
>> scanout-compatible in radeonsi's validateUsage() hook, rejecting the
>> import which will make Weston fall back to GLES composition.
>> That being said, st/dri's dri2_validate_usage() doesn't really fill me
>> with too much confidence.
> We don't really validate flags during DMABUF import. The idea is that
> all clients should know the flags since buffer creation, and have no
> reason to pass different flags during the import.

In that case, I guess the only option is to just make Gallium's dri2
st pass PIPE_USAGE_SCANOUT to every winsys allocation. This pessimises
allocation and disqualifies tiling/etc modes for buffers which can
never be scanout, but if there can be no validation (and thus we can't
reject a compositor which wishes to start using a client buffer for
scanout), then it's the only other option. Either that or just fail
every gbm_bo_import for scanout on Gallium.


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