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V4L/DVB (10571): v4l2-framework.txt: Fixes the videobuf init functions

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Documents the driver usage functions, instead of the generic one used
by the videobuf specific handlers.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Mauro Carvalho Chehab 2009-02-14 07:51:28 -03:00
parent 44061c05ac
commit a7a1c0e60c
1 changed files with 21 additions and 9 deletions
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30
Documentation/video4linux/v4l2-framework.txt
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@ -558,26 +558,38 @@ announcing that a new buffer were filled.
The irq handling code should handle the videobuf task lists, in order
to advice videobuf that a new frame were filled, in order to honor to a
request. The code is generally like this one:
if (list_empty(&dma_q->active))
if (list_empty(&dma_q->active))
return;
buf = list_entry(dma_q->active.next, struct vbuffer, vb.queue);
buf = list_entry(dma_q->active.next, struct vbuffer, vb.queue);
if (!waitqueue_active(&buf->vb.done))
if (!waitqueue_active(&buf->vb.done))
return;
/* Some logic to handle the buf may be needed here */
list_del(&buf->vb.queue);
do_gettimeofday(&buf->vb.ts);
wake_up(&buf->vb.done);
list_del(&buf->vb.queue);
do_gettimeofday(&buf->vb.ts);
wake_up(&buf->vb.done);
Those are the videobuffer functions used on drivers, implemented on
videobuf-core:
- videobuf_queue_core_init()
Initializes the videobuf infrastructure. This function should be
called before any other videobuf function.
- Videobuf init functions
videobuf_queue_sg_init()
Initializes the videobuf infrastructure. This function should be
called before any other videobuf function on drivers that uses DMA
Scatter/Gather buffers.
videobuf_queue_dma_contig_init
Initializes the videobuf infrastructure. This function should be
called before any other videobuf function on drivers that need DMA
contiguous buffers.
videobuf_queue_vmalloc_init()
Initializes the videobuf infrastructure. This function should be
called before any other videobuf function on USB (and other drivers)
that need a vmalloced type of videobuf.
- videobuf_iolock()
Prepares the videobuf memory for the proper method (read, mmap, overlay).