Messages in this thread | | | Subject | Re: [RFC PATCH v11 6/9] media: tegra: Add Tegra210 Video input driver | From | Sowjanya Komatineni <> | Date | Thu, 30 Apr 2020 13:08:39 -0700 |
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On 4/30/20 1:06 PM, Dmitry Osipenko wrote: > 30.04.2020 01:00, 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; >> + >> + set_freezable(); >> + >> + while (1) { >> + try_to_freeze(); >> + >> + /* >> + * Source is not streaming if error is non-zero. >> + * So, do not dequeue buffers on error and let the thread sleep >> + * till kthread stop signal is received. >> + */ >> + wait_event_interruptible(chan->start_wait, >> + kthread_should_stop() || >> + (!list_empty(&chan->capture) && >> + !err)); > ... >> +static void tegra_channel_buffer_queue(struct vb2_buffer *vb) >> +{ >> + struct tegra_vi_channel *chan = vb2_get_drv_priv(vb->vb2_queue); >> + struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb); >> + struct tegra_channel_buffer *buf = to_tegra_channel_buffer(vbuf); >> + >> + /* put buffer into the capture queue */ >> + spin_lock(&chan->start_lock); >> + list_add_tail(&buf->queue, &chan->capture); >> + spin_unlock(&chan->start_lock); >> + >> + /* wait up kthread for capture */ >> + wake_up_interruptible(&chan->start_wait); >> +} > The V4L doc says that buffers could be enqueued before streaming is > started. I guess it should be a trouble here, shouldn't it? > > https://elixir.bootlin.com/linux/v5.7-rc3/source/include/media/videobuf2-core.h#L379
what trouble are you referring here?
I dont think so as we set min buffers needed as 2 always there will be 2 per-queued buffers.
But buffers from this queue will be dequeued only when ready to processes in the capture thread
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