Re: [RFC PATCH v9 6/9] media: tegra: Add Tegra210 Video input driver

[Sowjanya Komatineni]

On 4/23/20 4:19 PM, Sowjanya Komatineni wrote:
> On 4/23/20 4:16 PM, Dmitry Osipenko wrote:
> > External email: Use caution opening links or attachments
> >
> >
> > 22.04.2020 09:18, Sowjanya Komatineni ÐÐÑÐÑ:
> > > +static int chan_capture_kthread_start(void *data)
> > > +{
> > > +ÂÂÂÂ struct tegra_vi_channel *chan = data;
> > > +ÂÂÂÂ struct tegra_channel_buffer *buf;
> > > +ÂÂÂÂ int err = 0;
> > > +
> > > +ÂÂÂÂ set_freezable();
> > > +
> > > +ÂÂÂÂ while (1) {
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂ try_to_freeze();
> > > +
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂ wait_event_interruptible(chan->start_wait,
> > > + !list_empty(&chan->capture) ||
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ kthread_should_stop());
> > > +
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂ if (kthread_should_stop())
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ break;
> > > +
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂ /*
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂ * Source is not streaming if error is non-zero.
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂ * So, do not dequeue buffers on capture error.
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂ */
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂ if (err)
> > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ continue;
> > This will result in an endless loop, I suppose it wasn't the intention.
>
> no it will not. on error we report vb2_queue_error which will do 
> streaming stop request.
>
> So thread will be stopped on streaming stop request thru kthread stop 
> signal
To be clear on error it reports vb2 queue error and waits for stop 
streaming to happen