06.04.2020 23:50, Sowjanya Komatineni пишет:
>
> On 4/6/20 1:45 PM, Dmitry Osipenko wrote:
>> External email: Use caution opening links or attachments
>>
>>
>> 04.04.2020 04:25, Sowjanya Komatineni пишет:
>>> +static int chan_capture_kthread_start(void *data)
>>> +{
>>> + struct tegra_vi_channel *chan = data;
>>> + struct tegra_channel_buffer *buf;
>>> + int err = 0;
>>> + int caps_inflight;
>>> +
>>> + set_freezable();
>>> +
>>> + while (1) {
>>> + try_to_freeze();
>>> +
>>> + wait_event_interruptible(chan->start_wait,
>>> + !list_empty(&chan->capture) ||
>>> + kthread_should_stop());
>>> + /*
>>> + * Frame start and MW_ACK_DONE syncpoint condition
>>> FIFOs are
>>> + * of max depth 2. So make sure max 2 capture requests are
>>> + * in process by the hardware at a time.
>>> + */
>>> + while (!(kthread_should_stop() ||
>>> list_empty(&chan->capture))) {
>>> + caps_inflight = chan->capture_reqs -
>>> chan->sequence;
>>> + /*
>>> + * Source is not streaming if error is non-zero.
>>> + * So, do not dequeue buffers on capture error
>>> or when
>>> + * syncpoint requests in FIFO are full.
>>> + */
>>> + if (err || caps_inflight >= SYNCPT_FIFO_DEPTH)
>>> + break;
>> Am I understanding correctly that this thread will take 100% CPU,
>> spinning here, if more than 2 frame-captures queued?
> on more than 2 frames captures, it breaks thread and on next wakeup it
> continues
The wait_event() won't wait if condition is true.
