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authorDavid S. Miller <davem@davemloft.net>2013-07-03 14:50:41 -0700
committerDavid S. Miller <davem@davemloft.net>2013-07-03 14:55:13 -0700
commit0c1072ae0242fbdffd9a0bba36e7a7033d287f9c (patch)
treee0f4dbdbf5078d4a707911177e7bdc17a70bdce5 /Documentation/DocBook
parentc50cd357887acf9fd7af3a5d492911bd825555a2 (diff)
parent8bb495e3f02401ee6f76d1b1d77f3ac9f079e376 (diff)
downloadop-kernel-dev-0c1072ae0242fbdffd9a0bba36e7a7033d287f9c.zip
op-kernel-dev-0c1072ae0242fbdffd9a0bba36e7a7033d287f9c.tar.gz
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts: drivers/net/ethernet/freescale/fec_main.c drivers/net/ethernet/renesas/sh_eth.c net/ipv4/gre.c The GRE conflict is between a bug fix (kfree_skb --> kfree_skb_list) and the splitting of the gre.c code into seperate files. The FEC conflict was two sets of changes adding ethtool support code in an "!CONFIG_M5272" CPP protected block. Finally the sh_eth.c conflict was between one commit add bits set in the .eesr_err_check mask whilst another commit removed the .tx_error_check member and assignments. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/DocBook')
-rw-r--r--Documentation/DocBook/media/v4l/dev-codec.xml35
-rw-r--r--Documentation/DocBook/media/v4l/v4l2.xml2
2 files changed, 23 insertions, 14 deletions
diff --git a/Documentation/DocBook/media/v4l/dev-codec.xml b/Documentation/DocBook/media/v4l/dev-codec.xml
index dca0ecd..ff44c16 100644
--- a/Documentation/DocBook/media/v4l/dev-codec.xml
+++ b/Documentation/DocBook/media/v4l/dev-codec.xml
@@ -1,18 +1,27 @@
<title>Codec Interface</title>
- <note>
- <title>Suspended</title>
+ <para>A V4L2 codec can compress, decompress, transform, or otherwise
+convert video data from one format into another format, in memory. Typically
+such devices are memory-to-memory devices (i.e. devices with the
+<constant>V4L2_CAP_VIDEO_M2M</constant> or <constant>V4L2_CAP_VIDEO_M2M_MPLANE</constant>
+capability set).
+</para>
- <para>This interface has been be suspended from the V4L2 API
-implemented in Linux 2.6 until we have more experience with codec
-device interfaces.</para>
- </note>
+ <para>A memory-to-memory video node acts just like a normal video node, but it
+supports both output (sending frames from memory to the codec hardware) and
+capture (receiving the processed frames from the codec hardware into memory)
+stream I/O. An application will have to setup the stream
+I/O for both sides and finally call &VIDIOC-STREAMON; for both capture and output
+to start the codec.</para>
- <para>A V4L2 codec can compress, decompress, transform, or otherwise
-convert video data from one format into another format, in memory.
-Applications send data to be converted to the driver through a
-&func-write; call, and receive the converted data through a
-&func-read; call. For efficiency a driver may also support streaming
-I/O.</para>
+ <para>Video compression codecs use the MPEG controls to setup their codec parameters
+(note that the MPEG controls actually support many more codecs than just MPEG).
+See <xref linkend="mpeg-controls"></xref>.</para>
- <para>[to do]</para>
+ <para>Memory-to-memory devices can often be used as a shared resource: you can
+open the video node multiple times, each application setting up their own codec properties
+that are local to the file handle, and each can use it independently from the others.
+The driver will arbitrate access to the codec and reprogram it whenever another file
+handler gets access. This is different from the usual video node behavior where the video properties
+are global to the device (i.e. changing something through one file handle is visible
+through another file handle).</para>
diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml
index bfc93cd..bfe823d 100644
--- a/Documentation/DocBook/media/v4l/v4l2.xml
+++ b/Documentation/DocBook/media/v4l/v4l2.xml
@@ -493,7 +493,7 @@ and discussions on the V4L mailing list.</revremark>
</partinfo>
<title>Video for Linux Two API Specification</title>
- <subtitle>Revision 3.9</subtitle>
+ <subtitle>Revision 3.10</subtitle>
<chapter id="common">
&sub-common;
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