Hi Hans,
On (20/06/02 11:51), Hans Verkuil wrote:
> Hi Sergey,
>
> While doing final testing for this patch series (together with the v4l-utils patch)
> I found one remaining issue:
Thanks for the report.
> > +static void set_buffer_cache_hints(struct vb2_queue *q,
> > + struct vb2_buffer *vb,
> > + struct v4l2_buffer *b)
> > +{
> > + /*
> > + * DMA exporter should take care of cache syncs, so we can avoid
> > + * explicit ->prepare()/->finish() syncs. For other ->memory types
> > + * we always need ->prepare() or/and ->finish() cache sync.
> > + */
> > + if (q->memory == VB2_MEMORY_DMABUF) {
> > + vb->need_cache_sync_on_finish = 0;
> > + vb->need_cache_sync_on_prepare = 0;
> > + return;
> > + }
> > +
> > + /*
> > + * Cache sync/invalidation flags are set by default in order to
> > + * preserve existing behaviour for old apps/drivers.
> > + */
> > + vb->need_cache_sync_on_prepare = 1;
> > + vb->need_cache_sync_on_finish = 1;
> > +
> > + if (!vb2_queue_allows_cache_hints(q)) {
> > + /*
> > + * Clear buffer cache flags if queue does not support user
> > + * space hints. That's to indicate to userspace that these
> > + * flags won't work.
> > + */
> > + b->flags &= ~V4L2_BUF_FLAG_NO_CACHE_INVALIDATE;
> > + b->flags &= ~V4L2_BUF_FLAG_NO_CACHE_CLEAN;
> > + return;
> > + }
>
> These two flags need to be cleared for VB2_MEMORY_DMABUF as well in the test above.
> This bug is causing v4l2-compliance failures (use the test-media script in contrib/test
> in v4l-utils: 'sudo test-media vim2m').
Sorry, Hans, do you suggest to have something like this:
if (q->memory == VB2_MEMORY_DMABUF) {
vb->need_cache_sync_on_finish = 0;
vb->need_cache_sync_on_prepare = 0;
b->flags &= ~V4L2_BUF_FLAG_NO_CACHE_INVALIDATE;
b->flags &= ~V4L2_BUF_FLAG_NO_CACHE_CLEAN;
return;
}
I didn't clear the ->flags there because we clear the vb flush/sync
flags: ->need_cache_sync_on_finish/prepare are zeros for DMABUF memory
type. Which is equivalent to passing V4L2_BUF_FLAG_NO_CACHE_INVALIDATE
V4L2_BUF_FLAG_NO_CACHE_CLEAN. IOW we would clearing both "vb's do cache
sync" and request's "do not cache sync".
> It's enough to post a v6.1 for this patch, everything else is fine.
Thanks!
-ss
