v4l has add a new IOCTL to export a buffer by using dmabuf.
This patch allow to use this new IOTCL if it has been defined in videodev2.h
I introduce a new IO mode (GST_V4L2_IO_DMABUF) to enable this way of working.
https://bugzilla.gnome.org/show_bug.cgi?id=693826
This was unused apparently and removed in the kernel in commit:
From 2b719d7baf490e24ce7d817c6337b7c87fda84c1 Mon Sep 17 00:00:00 2001
From: Sakari Ailus <sakari.ailus@iki.fi>
Date: Wed, 2 May 2012 09:40:03 -0300
Subject: [PATCH] [media] v4l: drop v4l2_buffer.input and V4L2_BUF_FLAG_INPUT
Remove input field in struct v4l2_buffer and flag V4L2_BUF_FLAG_INPUT which
tells the former is valid. The flag is used by no driver currently.
https://bugzilla.gnome.org/show_bug.cgi?id=681491
Conflicts:
sys/v4l2/gstv4l2bufferpool.c
Query the amount of available buffers when doing set_config(). This allows us to
configure the parent bufferpool with the number of buffers to preallocate.
Keep track of the provided allocator and use it when we need to allocate a
buffer in RW mode.
When we are can not allocate the requested max_buffers amount of buffers, make
sure we keep 2 buffers around in the pool and copy them into an output buffer.
This makes sure that we always have a buffer to capture into. We also need to
detect those copied buffers and unref them when they return to the pool.
Only free the queued buffers that we keep track of in our buffer array. for rw
io-mode, we do allocate buffers but we don't keep track of them in the buffer
array.
Add private replacements for deprecated functions such as
g_mutex_new(), g_mutex_free(), g_cond_new() etc., mostly
to avoid the deprecation warnings. We'll change these
over to the new API once we depend on glib >= 2.32.
When nobody is using our pool, activate it ourselves.
Avoid leaking the buffer array.
Set default pool configuration with caps.
Don't keep current_caps, core does that for us now.
Use the more specialized type for the bufferpool.
Use the size from the driver as the size of the image to read.
Don't configure the pool when created. This will be done in the setup_allocation
method later or by upstream for sinks.
Remove unused properties and variables. Bufferpool sizes are now configured in
the bufferpool by the elements in the pipeline. We might want to influence the
pool size later somehow.
Prefer to always use the default bufferpool queue for the _acquire function
because it properly supports unblocking when setting inactive etc. As a result,
we need to dequeue buffers and put them back in the bufferpool queue when we
have queued all buffers in the sink.
Rename some variables to more meaningfull names to avoid a problem with
freeing the wrong amount of buffers.
Remove old method, use neww _process method for the sink.
Inform the parent bufferpool class about the settings too. This is needed to let
it know about the max-buffers.
Allocate the negotiated max-buffers and initially mmap min-buffers. The idea is
that the bufferpool will allocate more when needed.
Improve debugging.
Only poll in capture mode, it does not seem to work in playback mode on this
beagleboard.
Add different transport methods to the bufferpool (MMAP and READ/WRITE)
Do more parsing of the bufferpool config.
Start and stop streaming based on the bufferpool state.
Make separate methods for getting a buffer from the pool and filling it with
data. This allows us to fill buffers from other pools too. Either use copy or
read to fill up the target buffers.
Add property to force a transfer mode in v4l2src.
Increase default number of buffers to 4.
Negotiate bufferpool and its properties in v4l2src.
