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authorLinus Torvalds <torvalds@linux-foundation.org>2014-04-04 20:50:07 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2014-04-04 20:50:07 +0400
commit3c83e61e67256e0bb08c46cc2db43b58fd617251 (patch)
tree0233e1e04e6449c60b01ff5dea8bea85bcf22f08 /Documentation/DocBook/media/v4l/vidioc-streamon.xml
parent4a4389abdd9822fdf3cc2ac6ed87eb811fd43acc (diff)
parenta83b93a7480441a47856dc9104bea970e84cda87 (diff)
downloadlinux-3c83e61e67256e0bb08c46cc2db43b58fd617251.tar.xz
Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media
Pull media updates from Mauro Carvalho Chehab: "The main set of series of patches for media subsystem, including: - document RC sysfs class - added an API to setup scancode to allow waking up systems using the Remote Controller - add API for SDR devices. Drivers are still on staging - some API improvements for getting EDID data from media inputs/outputs - new DVB frontend driver for drx-j (ATSC) - one driver (it913x/it9137) got removed, in favor of an improvement on another driver (af9035) - added a skeleton V4L2 PCI driver at documentation - added a dual flash driver (lm3646) - added a new IR driver (img-ir) - added an IR scancode decoder for the Sharp protocol - some improvements at the usbtv driver, to allow its core to be reused. - added a new SDR driver (rtl2832u_sdr) - added a new tuner driver (msi001) - several improvements at em28xx driver to fix PM support, device removal and to split the V4L2 specific bits into a separate sub-driver - one driver got converted to videobuf2 (s2255drv) - the e4000 tuner driver now follows an improved binding model - some fixes at V4L2 compat32 code - several fixes and enhancements at videobuf2 code - some cleanups at V4L2 API documentation - usual driver enhancements, new board additions and misc fixups" [ NOTE! This merge effective drops commit 4329b93b283c ("of: Reduce indentation in of_graph_get_next_endpoint"). The of_graph_get_next_endpoint() function was moved and renamed by commit fd9fdb78a9bf ("[media] of: move graph helpers from drivers/media/v4l2-core to drivers/of"). It was originally called v4l2_of_get_next_endpoint() and lived in the file drivers/media/v4l2-core/v4l2-of.c. In that original location, it was then fixed to support empty port nodes by commit b9db140c1e46 ("[media] v4l: of: Support empty port nodes"), and that commit clashes badly with the dropped "Reduce intendation" commit. I had to choose one or the other, and decided that the "Support empty port nodes" commit was more important ] * 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (426 commits) [media] em28xx-dvb: fix PCTV 461e tuner I2C binding Revert "[media] em28xx-dvb: fix PCTV 461e tuner I2C binding" [media] em28xx: fix PCTV 290e LNA oops [media] em28xx-dvb: fix PCTV 461e tuner I2C binding [media] m88ds3103: fix bug on .set_tone() [media] saa7134: fix WARN_ON during resume [media] v4l2-dv-timings: add module name, description, license [media] videodev2.h: add parenthesis around macro arguments [media] saa6752hs: depends on CRC32 [media] si4713: fix Kconfig dependencies [media] Sensoray 2255 uses videobuf2 [media] adv7180: free an interrupt on failure paths in init_device() [media] e4000: make VIDEO_V4L2 dependency optional [media] af9033: Don't export functions for the hardware filter [media] af9035: use af9033 PID filters [media] af9033: implement PID filter [media] rtl2832_sdr: do not use dynamic stack allocation [media] e4000: fix 32-bit build error [media] em28xx-audio: make sure audio is unmuted on open() [media] DocBook media: v4l2_format_sdr was renamed to v4l2_sdr_format ...
Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-streamon.xml')
-rw-r--r--Documentation/DocBook/media/v4l/vidioc-streamon.xml28
1 files changed, 22 insertions, 6 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-streamon.xml b/Documentation/DocBook/media/v4l/vidioc-streamon.xml
index 65dff55079d7..df2c63d07bac 100644
--- a/Documentation/DocBook/media/v4l/vidioc-streamon.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-streamon.xml
@@ -52,16 +52,24 @@
<para>The <constant>VIDIOC_STREAMON</constant> and
<constant>VIDIOC_STREAMOFF</constant> ioctl start and stop the capture
or output process during streaming (<link linkend="mmap">memory
-mapping</link> or <link linkend="userp">user pointer</link>) I/O.</para>
+mapping</link>, <link linkend="userp">user pointer</link> or
+<link linkend="dmabuf">DMABUF</link>) I/O.</para>
- <para>Specifically the capture hardware is disabled and no input
+ <para>Capture hardware is disabled and no input
buffers are filled (if there are any empty buffers in the incoming
queue) until <constant>VIDIOC_STREAMON</constant> has been called.
-Accordingly the output hardware is disabled, no video signal is
+Output hardware is disabled and no video signal is
produced until <constant>VIDIOC_STREAMON</constant> has been called.
The ioctl will succeed when at least one output buffer is in the
incoming queue.</para>
+ <para>Memory-to-memory devices will not start until
+<constant>VIDIOC_STREAMON</constant> has been called for both the capture
+and output stream types.</para>
+
+ <para>If <constant>VIDIOC_STREAMON</constant> fails then any already
+queued buffers will remain queued.</para>
+
<para>The <constant>VIDIOC_STREAMOFF</constant> ioctl, apart of
aborting or finishing any DMA in progress, unlocks any user pointer
buffers locked in physical memory, and it removes all buffers from the
@@ -70,14 +78,22 @@ dequeued yet will be lost, likewise all images enqueued for output but
not transmitted yet. I/O returns to the same state as after calling
&VIDIOC-REQBUFS; and can be restarted accordingly.</para>
+ <para>If buffers have been queued with &VIDIOC-QBUF; and
+<constant>VIDIOC_STREAMOFF</constant> is called without ever having
+called <constant>VIDIOC_STREAMON</constant>, then those queued buffers
+will also be removed from the incoming queue and all are returned to the
+same state as after calling &VIDIOC-REQBUFS; and can be restarted
+accordingly.</para>
+
<para>Both ioctls take a pointer to an integer, the desired buffer or
stream type. This is the same as &v4l2-requestbuffers;
<structfield>type</structfield>.</para>
<para>If <constant>VIDIOC_STREAMON</constant> is called when streaming
is already in progress, or if <constant>VIDIOC_STREAMOFF</constant> is called
-when streaming is already stopped, then the ioctl does nothing and 0 is
-returned.</para>
+when streaming is already stopped, then 0 is returned. Nothing happens in the
+case of <constant>VIDIOC_STREAMON</constant>, but <constant>VIDIOC_STREAMOFF</constant>
+will return queued buffers to their starting state as mentioned above.</para>
<para>Note that applications can be preempted for unknown periods right
before or after the <constant>VIDIOC_STREAMON</constant> or
@@ -93,7 +109,7 @@ synchronize with other events.</para>
<varlistentry>
<term><errorcode>EINVAL</errorcode></term>
<listitem>
- <para>The buffer<structfield>type</structfield> is not supported,
+ <para>The buffer <structfield>type</structfield> is not supported,
or no buffers have been allocated (memory mapping) or enqueued
(output) yet.</para>
</listitem>