[media] vb2: add thread support
In order to implement vb2 DVB support you need to be able to start a kernel thread that queues and dequeues buffers, calling a callback function for every buffer. This patch adds support for that. It's based on drivers/media/v4l2-core/videobuf-dvb.c, but with all the DVB specific stuff stripped out, thus making it much more generic. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
This commit is contained in:
Hans Verkuil
Mauro Carvalho Chehab
Родитель
5f26f2501b
Коммит
3415a89f48
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@ -6,6 +6,9 @@
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* Author: Pawel Osciak <pawel@osciak.com>
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* Marek Szyprowski <m.szyprowski@samsung.com>
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*
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* The vb2_thread implementation was based on code from videobuf-dvb.c:
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* (c) 2004 Gerd Knorr <kraxel@bytesex.org> [SUSE Labs]
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation.
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@ -18,6 +21,8 @@
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#include <linux/poll.h>
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#include <linux/slab.h>
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#include <linux/sched.h>
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#include <linux/freezer.h>
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#include <linux/kthread.h>
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#include <media/v4l2-dev.h>
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#include <media/v4l2-fh.h>
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@ -3005,6 +3010,147 @@ size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count,
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}
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EXPORT_SYMBOL_GPL(vb2_write);
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struct vb2_threadio_data {
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struct task_struct *thread;
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vb2_thread_fnc fnc;
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void *priv;
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bool stop;
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};
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static int vb2_thread(void *data)
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{
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struct vb2_queue *q = data;
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struct vb2_threadio_data *threadio = q->threadio;
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struct vb2_fileio_data *fileio = q->fileio;
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bool set_timestamp = false;
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int prequeue = 0;
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int index = 0;
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int ret = 0;
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if (V4L2_TYPE_IS_OUTPUT(q->type)) {
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prequeue = q->num_buffers;
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set_timestamp =
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(q->timestamp_flags & V4L2_BUF_FLAG_TIMESTAMP_MASK) ==
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V4L2_BUF_FLAG_TIMESTAMP_COPY;
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}
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set_freezable();
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for (;;) {
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struct vb2_buffer *vb;
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/*
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* Call vb2_dqbuf to get buffer back.
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*/
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memset(&fileio->b, 0, sizeof(fileio->b));
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fileio->b.type = q->type;
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fileio->b.memory = q->memory;
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if (prequeue) {
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fileio->b.index = index++;
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prequeue--;
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} else {
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call_void_qop(q, wait_finish, q);
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ret = vb2_internal_dqbuf(q, &fileio->b, 0);
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call_void_qop(q, wait_prepare, q);
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dprintk(5, "file io: vb2_dqbuf result: %d\n", ret);
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}
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if (threadio->stop)
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break;
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if (ret)
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break;
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try_to_freeze();
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vb = q->bufs[fileio->b.index];
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if (!(fileio->b.flags & V4L2_BUF_FLAG_ERROR))
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ret = threadio->fnc(vb, threadio->priv);
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if (ret)
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break;
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call_void_qop(q, wait_finish, q);
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if (set_timestamp)
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v4l2_get_timestamp(&fileio->b.timestamp);
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ret = vb2_internal_qbuf(q, &fileio->b);
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call_void_qop(q, wait_prepare, q);
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if (ret)
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break;
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}
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/* Hmm, linux becomes *very* unhappy without this ... */
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while (!kthread_should_stop()) {
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set_current_state(TASK_INTERRUPTIBLE);
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schedule();
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}
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return 0;
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}
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/*
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* This function should not be used for anything else but the videobuf2-dvb
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* support. If you think you have another good use-case for this, then please
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* contact the linux-media mailinglist first.
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*/
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int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv,
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const char *thread_name)
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{
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struct vb2_threadio_data *threadio;
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int ret = 0;
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if (q->threadio)
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return -EBUSY;
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if (vb2_is_busy(q))
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return -EBUSY;
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if (WARN_ON(q->fileio))
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return -EBUSY;
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threadio = kzalloc(sizeof(*threadio), GFP_KERNEL);
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if (threadio == NULL)
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return -ENOMEM;
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threadio->fnc = fnc;
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threadio->priv = priv;
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ret = __vb2_init_fileio(q, !V4L2_TYPE_IS_OUTPUT(q->type));
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dprintk(3, "file io: vb2_init_fileio result: %d\n", ret);
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if (ret)
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goto nomem;
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q->threadio = threadio;
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threadio->thread = kthread_run(vb2_thread, q, "vb2-%s", thread_name);
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if (IS_ERR(threadio->thread)) {
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ret = PTR_ERR(threadio->thread);
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threadio->thread = NULL;
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goto nothread;
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}
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return 0;
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nothread:
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__vb2_cleanup_fileio(q);
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nomem:
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kfree(threadio);
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return ret;
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}
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EXPORT_SYMBOL_GPL(vb2_thread_start);
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int vb2_thread_stop(struct vb2_queue *q)
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{
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struct vb2_threadio_data *threadio = q->threadio;
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struct vb2_fileio_data *fileio = q->fileio;
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int err;
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if (threadio == NULL)
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return 0;
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call_void_qop(q, wait_finish, q);
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threadio->stop = true;
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vb2_internal_streamoff(q, q->type);
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call_void_qop(q, wait_prepare, q);
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q->fileio = NULL;
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fileio->req.count = 0;
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vb2_reqbufs(q, &fileio->req);
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kfree(fileio);
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err = kthread_stop(threadio->thread);
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threadio->thread = NULL;
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kfree(threadio);
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q->fileio = NULL;
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q->threadio = NULL;
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return err;
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}
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EXPORT_SYMBOL_GPL(vb2_thread_stop);
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/*
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* The following functions are not part of the vb2 core API, but are helper
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@ -20,6 +20,7 @@
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struct vb2_alloc_ctx;
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struct vb2_fileio_data;
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struct vb2_threadio_data;
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/**
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* struct vb2_mem_ops - memory handling/memory allocator operations
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@ -375,6 +376,7 @@ struct v4l2_fh;
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* @start_streaming_called: start_streaming() was called successfully and we
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* started streaming.
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* @fileio: file io emulator internal data, used only if emulator is active
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* @threadio: thread io internal data, used only if thread is active
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*/
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struct vb2_queue {
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enum v4l2_buf_type type;
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@ -411,6 +413,7 @@ struct vb2_queue {
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unsigned int start_streaming_called:1;
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struct vb2_fileio_data *fileio;
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struct vb2_threadio_data *threadio;
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#ifdef CONFIG_VIDEO_ADV_DEBUG
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/*
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@ -461,6 +464,35 @@ size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
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loff_t *ppos, int nonblock);
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size_t vb2_write(struct vb2_queue *q, const char __user *data, size_t count,
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loff_t *ppos, int nonblock);
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/**
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* vb2_thread_fnc - callback function for use with vb2_thread
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*
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* This is called whenever a buffer is dequeued in the thread.
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*/
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typedef int (*vb2_thread_fnc)(struct vb2_buffer *vb, void *priv);
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/**
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* vb2_thread_start() - start a thread for the given queue.
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* @q: videobuf queue
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* @fnc: callback function
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* @priv: priv pointer passed to the callback function
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* @thread_name:the name of the thread. This will be prefixed with "vb2-".
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*
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* This starts a thread that will queue and dequeue until an error occurs
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* or @vb2_thread_stop is called.
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*
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* This function should not be used for anything else but the videobuf2-dvb
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* support. If you think you have another good use-case for this, then please
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* contact the linux-media mailinglist first.
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*/
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int vb2_thread_start(struct vb2_queue *q, vb2_thread_fnc fnc, void *priv,
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const char *thread_name);
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/**
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* vb2_thread_stop() - stop the thread for the given queue.
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* @q: videobuf queue
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*/
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int vb2_thread_stop(struct vb2_queue *q);
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/**
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* vb2_is_streaming() - return streaming status of the queue
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