Messages in this thread | | | Date | Mon, 15 Jan 2018 10:01:11 -0200 | From | Gustavo Padovan <> | Subject | Re: [PATCH v7 1/6] [media] vb2: add is_unordered callback for drivers |
| |
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.
I understand your concern. My question is how dangerous will it be. If you are building a product you will make the changes in the driver if they are not there yet, or if it is a distribution you'd never know which driver/format you are using so you should be prepared for everything.
AFAIK all Capture drivers are ordered and that is where I think fences is most useful.
Gustavo
| |