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Subject: Re: [RFC PATCH v11 6/9] media: tegra: Add Tegra210 Video input driver
From:   Dmitry Osipenko <digetx@gmail.com>
To:     Sowjanya Komatineni <skomatineni@nvidia.com>,
        thierry.reding@gmail.com, jonathanh@nvidia.com, frankc@nvidia.com,
        hverkuil@xs4all.nl, sakari.ailus@iki.fi, helen.koike@collabora.com
Cc:     sboyd@kernel.org, linux-media@vger.kernel.org,
        devicetree@vger.kernel.org, linux-clk@vger.kernel.org,
        linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org
References: <1588197606-32124-1-git-send-email-skomatineni@nvidia.com>
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Message-ID: <4da289e6-036f-853b-beb4-379d6462adb0@gmail.com>
Date:   Thu, 30 Apr 2020 17:02:19 +0300
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30.04.2020 16:56, Dmitry Osipenko пишет:
> 30.04.2020 01:00, Sowjanya Komatineni пишет:
>> +static int chan_capture_kthread_finish(void *data)
>> +{
>> +	struct tegra_vi_channel *chan = data;
>> +	struct tegra_channel_buffer *buf;
>> +
>> +	set_freezable();
>> +
>> +	while (1) {
>> +		try_to_freeze();
> 
> I guess it won't be great to freeze in the middle of a capture process, so:
> 		if (list_empty(&chan->done))
> 			try_to_freeze();

And here should be some locking protection in order not race with the
chan_capture_kthread_start because kthread_finish could freeze before
kthread_start.

>> +		wait_event_interruptible(chan->done_wait,
>> +					 !list_empty(&chan->done) ||
>> +					 kthread_should_stop());
>> +
>> +		/* dequeue buffers and finish capture */
>> +		buf = dequeue_buf_done(chan);
>> +		while (buf) {
>> +			tegra_channel_capture_done(chan, buf);
>> +			buf = dequeue_buf_done(chan);
>> +		}
>> +
>> +		if (kthread_should_stop())
>> +			break;
>> +	}
>> +
>> +	return 0;
>> +}
>