Messages in this thread | | | From | Alexandre Courbot <> | Date | Tue, 16 Jan 2018 11:35:33 +0900 | Subject | Re: [PATCH v7 1/6] [media] vb2: add is_unordered callback for drivers |
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On Mon, Jan 15, 2018 at 9:01 PM, Gustavo Padovan <gustavo@padovan.org> wrote: > 2018-01-15 Alexandre Courbot <acourbot@chromium.org>: > >> On Thu, Jan 11, 2018 at 1:07 AM, Gustavo Padovan <gustavo@padovan.org> wrote: >> > From: Gustavo Padovan <gustavo.padovan@collabora.com> >> > >> > Explicit synchronization benefits a lot from ordered queues, they fit >> > better in a pipeline with DRM for example so create a opt-in way for >> > drivers notify videobuf2 that the queue is unordered. >> > >> > Drivers don't need implement it if the queue is ordered. >> >> This is going to make user-space believe that *all* vb2 drivers use >> ordered queues by default, at least until non-ordered drivers catch up >> with this change. Wouldn't it be less dangerous to do the opposite >> (make queues non-ordered by default)? > > The rational behind this decision was because most formats/drivers are > ordered so only a small amount of drivers need to changed. I think this > was proposed by Hans on the Media Summit.
As long as all concerned drivers are updated we should be on the safe side. At first I was surprised that we expose the ordering feature in a negative tense, but if the vast majority of devices are ordered this probably makes sense.
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