137d1cb19d
Add a waitqueue to wait on when there are no buffers in the buffer queue. DQBUF waits on this queue without holding vb_lock to allow a QBUF to happen. Once a buffer has been queued we recheck that the queue is still streaming and wait on the new buffer's waitqueue while holding the vb_lock. The driver should come along in a timely manner and put the buffer into its next state finishing the DQBUF. By implementing this waitqueue it also brings the videobuf DQBUF up to spec and it now blocks on O_NONBLOCK even when no buffers have been queued via QBUF: "By default VIDIOC_DQBUF blocks when no buffer is in the outgoing queue." - V4L2 spec Signed-off-by: Brandon Philips <bphilips@suse.de> CC: Trent Piepho <xyzzy@speakeasy.org> CC: Carl Karsten <carl@personnelware.com> CC: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
243 lines
7.2 KiB
C
243 lines
7.2 KiB
C
/*
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* generic helper functions for handling video4linux capture buffers
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*
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* (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
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*
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* Highly based on video-buf written originally by:
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* (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
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* (c) 2006 Mauro Carvalho Chehab, <mchehab@infradead.org>
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* (c) 2006 Ted Walther and John Sokol
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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; either version 2
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*/
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#include <linux/poll.h>
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#ifdef CONFIG_VIDEO_V4L1_COMPAT
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#include <linux/videodev.h>
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#endif
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#include <linux/videodev2.h>
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#define UNSET (-1U)
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struct videobuf_buffer;
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struct videobuf_queue;
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/* --------------------------------------------------------------------- */
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/*
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* A small set of helper functions to manage video4linux buffers.
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*
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* struct videobuf_buffer holds the data structures used by the helper
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* functions, additionally some commonly used fields for v4l buffers
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* (width, height, lists, waitqueue) are in there. That struct should
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* be used as first element in the drivers buffer struct.
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*
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* about the mmap helpers (videobuf_mmap_*):
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*
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* The mmaper function allows to map any subset of contingous buffers.
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* This includes one mmap() call for all buffers (which the original
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* video4linux API uses) as well as one mmap() for every single buffer
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* (which v4l2 uses).
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*
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* If there is a valid mapping for a buffer, buffer->baddr/bsize holds
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* userspace address + size which can be feeded into the
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* videobuf_dma_init_user function listed above.
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*
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*/
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struct videobuf_mapping {
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unsigned int count;
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unsigned long start;
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unsigned long end;
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struct videobuf_queue *q;
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};
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enum videobuf_state {
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VIDEOBUF_NEEDS_INIT = 0,
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VIDEOBUF_PREPARED = 1,
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VIDEOBUF_QUEUED = 2,
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VIDEOBUF_ACTIVE = 3,
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VIDEOBUF_DONE = 4,
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VIDEOBUF_ERROR = 5,
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VIDEOBUF_IDLE = 6,
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};
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struct videobuf_buffer {
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unsigned int i;
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u32 magic;
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/* info about the buffer */
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unsigned int width;
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unsigned int height;
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unsigned int bytesperline; /* use only if != 0 */
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unsigned long size;
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unsigned int input;
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enum v4l2_field field;
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enum videobuf_state state;
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struct list_head stream; /* QBUF/DQBUF list */
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/* touched by irq handler */
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struct list_head queue;
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wait_queue_head_t done;
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unsigned int field_count;
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struct timeval ts;
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/* Memory type */
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enum v4l2_memory memory;
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/* buffer size */
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size_t bsize;
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/* buffer offset (mmap + overlay) */
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size_t boff;
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/* buffer addr (userland ptr!) */
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unsigned long baddr;
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/* for mmap'ed buffers */
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struct videobuf_mapping *map;
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/* Private pointer to allow specific methods to store their data */
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int privsize;
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void *priv;
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};
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struct videobuf_queue_ops {
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int (*buf_setup)(struct videobuf_queue *q,
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unsigned int *count, unsigned int *size);
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int (*buf_prepare)(struct videobuf_queue *q,
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struct videobuf_buffer *vb,
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enum v4l2_field field);
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void (*buf_queue)(struct videobuf_queue *q,
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struct videobuf_buffer *vb);
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void (*buf_release)(struct videobuf_queue *q,
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struct videobuf_buffer *vb);
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};
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#define MAGIC_QTYPE_OPS 0x12261003
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/* Helper operations - device type dependent */
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struct videobuf_qtype_ops {
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u32 magic;
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void* (*alloc) (size_t size);
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int (*iolock) (struct videobuf_queue* q,
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struct videobuf_buffer *vb,
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struct v4l2_framebuffer *fbuf);
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int (*mmap) (struct videobuf_queue *q,
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unsigned int *count,
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unsigned int *size,
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enum v4l2_memory memory);
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int (*sync) (struct videobuf_queue* q,
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struct videobuf_buffer *buf);
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int (*video_copy_to_user)(struct videobuf_queue *q,
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char __user *data,
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size_t count,
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int nonblocking);
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int (*copy_stream) (struct videobuf_queue *q,
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char __user *data,
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size_t count,
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size_t pos,
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int vbihack,
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int nonblocking);
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int (*mmap_free) (struct videobuf_queue *q);
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int (*mmap_mapper) (struct videobuf_queue *q,
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struct vm_area_struct *vma);
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};
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struct videobuf_queue {
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struct mutex vb_lock;
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spinlock_t *irqlock;
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struct device *dev;
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wait_queue_head_t wait; /* wait if queue is empty */
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enum v4l2_buf_type type;
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unsigned int inputs; /* for V4L2_BUF_FLAG_INPUT */
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unsigned int msize;
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enum v4l2_field field;
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enum v4l2_field last; /* for field=V4L2_FIELD_ALTERNATE */
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struct videobuf_buffer *bufs[VIDEO_MAX_FRAME];
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struct videobuf_queue_ops *ops;
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struct videobuf_qtype_ops *int_ops;
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unsigned int streaming:1;
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unsigned int reading:1;
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unsigned int is_mmapped:1;
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/* capture via mmap() + ioctl(QBUF/DQBUF) */
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struct list_head stream;
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/* capture via read() */
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unsigned int read_off;
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struct videobuf_buffer *read_buf;
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/* driver private data */
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void *priv_data;
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};
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int videobuf_waiton(struct videobuf_buffer *vb, int non_blocking, int intr);
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int videobuf_iolock(struct videobuf_queue* q, struct videobuf_buffer *vb,
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struct v4l2_framebuffer *fbuf);
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void *videobuf_alloc(struct videobuf_queue* q);
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void videobuf_queue_core_init(struct videobuf_queue *q,
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struct videobuf_queue_ops *ops,
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struct device *dev,
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spinlock_t *irqlock,
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enum v4l2_buf_type type,
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enum v4l2_field field,
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unsigned int msize,
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void *priv,
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struct videobuf_qtype_ops *int_ops);
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int videobuf_queue_is_busy(struct videobuf_queue *q);
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void videobuf_queue_cancel(struct videobuf_queue *q);
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enum v4l2_field videobuf_next_field(struct videobuf_queue *q);
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int videobuf_reqbufs(struct videobuf_queue *q,
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struct v4l2_requestbuffers *req);
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int videobuf_querybuf(struct videobuf_queue *q, struct v4l2_buffer *b);
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int videobuf_qbuf(struct videobuf_queue *q,
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struct v4l2_buffer *b);
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int videobuf_dqbuf(struct videobuf_queue *q,
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struct v4l2_buffer *b, int nonblocking);
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#ifdef CONFIG_VIDEO_V4L1_COMPAT
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int videobuf_cgmbuf(struct videobuf_queue *q,
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struct video_mbuf *mbuf, int count);
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#endif
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int videobuf_streamon(struct videobuf_queue *q);
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int videobuf_streamoff(struct videobuf_queue *q);
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void videobuf_stop(struct videobuf_queue *q);
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int videobuf_read_start(struct videobuf_queue *q);
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void videobuf_read_stop(struct videobuf_queue *q);
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ssize_t videobuf_read_stream(struct videobuf_queue *q,
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char __user *data, size_t count, loff_t *ppos,
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int vbihack, int nonblocking);
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ssize_t videobuf_read_one(struct videobuf_queue *q,
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char __user *data, size_t count, loff_t *ppos,
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int nonblocking);
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unsigned int videobuf_poll_stream(struct file *file,
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struct videobuf_queue *q,
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poll_table *wait);
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int videobuf_mmap_setup(struct videobuf_queue *q,
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unsigned int bcount, unsigned int bsize,
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enum v4l2_memory memory);
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int videobuf_mmap_free(struct videobuf_queue *q);
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int videobuf_mmap_mapper(struct videobuf_queue *q,
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struct vm_area_struct *vma);
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/* --------------------------------------------------------------------- */
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/*
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* Local variables:
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* c-basic-offset: 8
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* End:
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*/
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