[libcamera-devel] [RFC v1 5/7] py: Add 'nonblocking' argument to get_ready_requests()

[David Plowman]

Ah, I was just thinking of finding out how to do that, I'll give it a
try. Thanks!

David

On Thu, 30 Jun 2022 at 07:13, Tomi Valkeinen
<tomi.valkeinen at ideasonboard.com> wrote:
>
> On 28/06/2022 11:16, David Plowman wrote:
> > Hi everyone
> >
> > Sorry for not taking part in this discussion rather more, and thanks
> > to those who have! I think I was asked further back if I had an
> > opinion, so let me try and explain how I see things.
> >
> > Actually I don't have any particularly strong opinions, other than
> > that I want things to work and to be easy to use. And if they stopped
> > changing, that would be nice too!!
> >
> > I was actually OK with the previous version where get_ready_requests
> > was non-blocking, it's only the more recent version that causes me
> > some trouble because I can't simply flush out any lurking requests
> > after stopping the camera - because there might not be any and I will
> > simply lock up the system.
>
> Btw, while we're discussing and fixing this issue, you can also do a
> check in Python:
>
>          import selectors
>          sel = selectors.DefaultSelector()
>          sel.register(cm.event_fd, selectors.EVENT_READ)
>          events = sel.select(0)
>          if events:
>              print("get_ready_requests doesn't block")
>          else:
>              print("get_ready_requests may block")
>
> This could be used to avoid calling get_ready_requests when it may block.
>
>   Tomi