From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: [RFC PATCH v6 6/9] media: tegra: Add Tegra210 Video input driver
Date: Mon, 6 Apr 2020 23:45:24 +0300
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To: Sowjanya Komatineni <skomatineni-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>, thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, frankc-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, hverkuil-qWit8jRvyhVmR6Xm/wNWPw@public.gmane.org, sakari.ailus-X3B1VOXEql0@public.gmane.org, helen.koike-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org
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List-Id: linux-tegra@vger.kernel.org

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?