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authorMauro Carvalho Chehab <mchehab@redhat.com>2011-06-25 14:11:52 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2011-07-27 17:53:16 -0300
commitc20eb18ce1db6792db69f0574f7e955e9f92a213 (patch)
tree2dd4b7aae9a3b18a0d01652a61090f637fe4289d /Documentation/DocBook/media/v4l/vidioc-querycap.xml
parent29834c1ac7589c72996c5d02349d63fd397ef131 (diff)
[media] DocBook/v4l: Document the new system-wide version behavior
Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-querycap.xml')
-rw-r--r--Documentation/DocBook/media/v4l/vidioc-querycap.xml15
1 files changed, 9 insertions, 6 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-querycap.xml b/Documentation/DocBook/media/v4l/vidioc-querycap.xml
index f29f1b86213..7aa697323c7 100644
--- a/Documentation/DocBook/media/v4l/vidioc-querycap.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-querycap.xml
@@ -67,9 +67,8 @@ driver is not compatible with this specification the ioctl returns an
<entry><para>Name of the driver, a unique NUL-terminated
ASCII string. For example: "bttv". Driver specific applications can
use this information to verify the driver identity. It is also useful
-to work around known bugs, or to identify drivers in error reports.
-The driver version is stored in the <structfield>version</structfield>
-field.</para><para>Storing strings in fixed sized arrays is bad
+to work around known bugs, or to identify drivers in error reports.</para>
+<para>Storing strings in fixed sized arrays is bad
practice but unavoidable here. Drivers and applications should take
precautions to never read or write beyond the end of the array and to
make sure the strings are properly NUL-terminated.</para></entry>
@@ -100,9 +99,13 @@ empty string (<structfield>bus_info</structfield>[0] = 0).<!-- XXX pci_dev->slot
<row>
<entry>__u32</entry>
<entry><structfield>version</structfield></entry>
- <entry><para>Version number of the driver. Together with
-the <structfield>driver</structfield> field this identifies a
-particular driver. The version number is formatted using the
+ <entry><para>Version number of the driver.</para>
+<para>Starting on kernel 3.1, the version reported is provided per
+V4L2 subsystem, following the same Kernel numberation scheme. However, it
+should not always return the same version as the kernel, if, for example,
+an stable or distribution-modified kernel uses the V4L2 stack from a
+newer kernel.</para>
+<para>The version number is formatted using the
<constant>KERNEL_VERSION()</constant> macro:</para></entry>
</row>
<row>