diff options
author | Hans Verkuil <hans.verkuil@cisco.com> | 2012-01-11 09:45:05 (GMT) |
---|---|---|
committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2012-01-23 18:34:27 (GMT) |
commit | 583aa3a9b5ca846a84f7dd87bdc4b75dca07b011 (patch) | |
tree | a86d9d5f2e9817e9faf9d2e06d212d4380924fe9 /Documentation/DocBook | |
parent | 93596ef7db3e9bcc9306c3e93cf28ce1048858b6 (diff) | |
download | linux-fsl-qoriq-583aa3a9b5ca846a84f7dd87bdc4b75dca07b011.tar.xz |
[media] V4L2: Add per-device-node capabilities
If V4L2_CAP_DEVICE_CAPS is set, then the new device_caps field is filled with
the capabilities of the opened device node.
The capabilities field traditionally contains the capabilities of the physical
device, being a superset of all capabilities available at the several device
nodes. E.g., if you open /dev/video0, then if it contains VBI caps then that means
that there is a corresponding vbi node as well. And the capabilities field of
both the video and vbi nodes should contain identical caps.
However, it would be very useful to also have a capabilities field that contains
just the caps for the currently open device, hence the new CAP bit and field.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/DocBook')
-rw-r--r-- | Documentation/DocBook/media/v4l/compat.xml | 4 | ||||
-rw-r--r-- | Documentation/DocBook/media/v4l/v4l2.xml | 9 | ||||
-rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-querycap.xml | 36 |
3 files changed, 45 insertions, 4 deletions
diff --git a/Documentation/DocBook/media/v4l/compat.xml b/Documentation/DocBook/media/v4l/compat.xml index c736380..c93298f 100644 --- a/Documentation/DocBook/media/v4l/compat.xml +++ b/Documentation/DocBook/media/v4l/compat.xml @@ -2393,6 +2393,10 @@ details.</para> to the <link linkend="control">User controls class</link>. </para> </listitem> + <listitem> + <para>Added the device_caps field to struct v4l2_capabilities and added the new + V4L2_CAP_DEVICE_CAPS capability.</para> + </listitem> </orderedlist> </section> diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml index e97c512..dce3fef 100644 --- a/Documentation/DocBook/media/v4l/v4l2.xml +++ b/Documentation/DocBook/media/v4l/v4l2.xml @@ -128,6 +128,13 @@ structs, ioctls) must be noted in more detail in the history chapter applications. --> <revision> + <revnumber>3.3</revnumber> + <date>2012-01-11</date> + <authorinitials>hv</authorinitials> + <revremark>Added device_caps field to struct v4l2_capabilities.</revremark> + </revision> + + <revision> <revnumber>3.2</revnumber> <date>2011-08-26</date> <authorinitials>hv</authorinitials> @@ -417,7 +424,7 @@ and discussions on the V4L mailing list.</revremark> </partinfo> <title>Video for Linux Two API Specification</title> - <subtitle>Revision 3.2</subtitle> + <subtitle>Revision 3.3</subtitle> <chapter id="common"> &sub-common; diff --git a/Documentation/DocBook/media/v4l/vidioc-querycap.xml b/Documentation/DocBook/media/v4l/vidioc-querycap.xml index e3664d6..4643505 100644 --- a/Documentation/DocBook/media/v4l/vidioc-querycap.xml +++ b/Documentation/DocBook/media/v4l/vidioc-querycap.xml @@ -124,12 +124,35 @@ printf ("Version: %u.%u.%u\n", <row> <entry>__u32</entry> <entry><structfield>capabilities</structfield></entry> - <entry>Device capabilities, see <xref - linkend="device-capabilities" />.</entry> + <entry>Available capabilities of the physical device as a whole, see <xref + linkend="device-capabilities" />. The same physical device can export + multiple devices in /dev (e.g. /dev/videoX, /dev/vbiY and /dev/radioZ). + The <structfield>capabilities</structfield> field should contain a union + of all capabilities available around the several V4L2 devices exported + to userspace. + For all those devices the <structfield>capabilities</structfield> field + returns the same set of capabilities. This allows applications to open + just one of the devices (typically the video device) and discover whether + video, vbi and/or radio are also supported. + </entry> </row> <row> <entry>__u32</entry> - <entry><structfield>reserved</structfield>[4]</entry> + <entry><structfield>device_caps</structfield></entry> + <entry>Device capabilities of the opened device, see <xref + linkend="device-capabilities" />. Should contain the available capabilities + of that specific device node. So, for example, <structfield>device_caps</structfield> + of a radio device will only contain radio related capabilities and + no video or vbi capabilities. This field is only set if the <structfield>capabilities</structfield> + field contains the <constant>V4L2_CAP_DEVICE_CAPS</constant> capability. + Only the <structfield>capabilities</structfield> field can have the + <constant>V4L2_CAP_DEVICE_CAPS</constant> capability, <structfield>device_caps</structfield> + will never set <constant>V4L2_CAP_DEVICE_CAPS</constant>. + </entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[3]</entry> <entry>Reserved for future extensions. Drivers must set this array to zero.</entry> </row> @@ -276,6 +299,13 @@ linkend="async">asynchronous</link> I/O methods.</entry> <entry>The device supports the <link linkend="mmap">streaming</link> I/O method.</entry> </row> + <row> + <entry><constant>V4L2_CAP_DEVICE_CAPS</constant></entry> + <entry>0x80000000</entry> + <entry>The driver fills the <structfield>device_caps</structfield> + field. This capability can only appear in the <structfield>capabilities</structfield> + field and never in the <structfield>device_caps</structfield> field.</entry> + </row> </tbody> </tgroup> </table> |