From: Hans Verkuil <hans.verk...@cisco.com>
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.verk...@cisco.com>
---
Documentation/DocBook/media/v4l/compat.xml | 9 +++++
Documentation/DocBook/media/v4l/v4l2.xml | 9 ++++-
.../DocBook/media/v4l/vidioc-querycap.xml | 36 ++++++++++++++++++--
drivers/media/video/cx231xx/cx231xx-417.c | 1 -
drivers/media/video/pvrusb2/pvrusb2-v4l2.c | 1 -
drivers/media/video/v4l2-ioctl.c | 6 ++-
include/linux/videodev2.h | 29 +++++++++++-----
7 files changed, 74 insertions(+), 17 deletions(-)
diff --git a/Documentation/DocBook/media/v4l/compat.xml
b/Documentation/DocBook/media/v4l/compat.xml
index 8b44a43..d122a3e 100644
--- a/Documentation/DocBook/media/v4l/compat.xml
+++ b/Documentation/DocBook/media/v4l/compat.xml
@@ -2378,6 +2378,15 @@ that used it. It was originally scheduled for removal in
2.6.35.
</listitem>
</orderedlist>
</section>
+ <section>
+ <title>V4L2 in Linux 3.3</title>
+ <orderedlist>
+ <listitem>
+ <para>Added the device_caps field to struct v4l2_capabilities and
added the new
+ V4L2_CAP_DEVICE_CAPS capability.</para>
+ </listitem>
+ </orderedlist>
+ </section>
<section id="other">
<title>Relation of V4L2 to other Linux multimedia APIs</title>
diff --git a/Documentation/DocBook/media/v4l/v4l2.xml
b/Documentation/DocBook/media/v4l/v4l2.xml
index 2ab365c..6b6e584 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>2011-11-22</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>
diff --git a/drivers/media/video/cx231xx/cx231xx-417.c
b/drivers/media/video/cx231xx/cx231xx-417.c
index f8f0e59..d4327da 100644
--- a/drivers/media/video/cx231xx/cx231xx-417.c
+++ b/drivers/media/video/cx231xx/cx231xx-417.c
@@ -1686,7 +1686,6 @@ static struct v4l2_capability pvr_capability = {
.capabilities = (V4L2_CAP_VIDEO_CAPTURE |
V4L2_CAP_TUNER | V4L2_CAP_AUDIO | V4L2_CAP_RADIO |
V4L2_CAP_STREAMING | V4L2_CAP_READWRITE),
- .reserved = {0, 0, 0, 0}
};
static int vidioc_querycap(struct file *file, void *priv,
struct v4l2_capability *cap)
diff --git a/drivers/media/video/pvrusb2/pvrusb2-v4l2.c
b/drivers/media/video/pvrusb2/pvrusb2-v4l2.c
index 6d66617..e1111d9 100644
--- a/drivers/media/video/pvrusb2/pvrusb2-v4l2.c
+++ b/drivers/media/video/pvrusb2/pvrusb2-v4l2.c
@@ -96,7 +96,6 @@ static struct v4l2_capability pvr_capability ={
.capabilities = (V4L2_CAP_VIDEO_CAPTURE |
V4L2_CAP_TUNER | V4L2_CAP_AUDIO | V4L2_CAP_RADIO |
V4L2_CAP_READWRITE),
- .reserved = {0,0,0,0}
};
static struct v4l2_fmtdesc pvr_fmtdesc [] = {
diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c
index e1da8fc..ae716c2 100644
--- a/drivers/media/video/v4l2-ioctl.c
+++ b/drivers/media/video/v4l2-ioctl.c
@@ -538,10 +538,12 @@ static long __video_do_ioctl(struct file *file,
if (!ret)
dbgarg(cmd, "driver=%s, card=%s, bus=%s, "
"version=0x%08x, "
- "capabilities=0x%08x\n",
+ "capabilities=0x%08x, "
+ "device_caps=0x%08x\n",
cap->driver, cap->card, cap->bus_info,
cap->version,
- cap->capabilities);
+ cap->capabilities,
+ cap->device_caps);
break;
}
diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
index 4b752d5..c185707 100644
--- a/include/linux/videodev2.h
+++ b/include/linux/videodev2.h
@@ -235,16 +235,25 @@ struct v4l2_fract {
__u32 denominator;
};
-/*
- * D R I V E R C A P A B I L I T I E S
- */
+/**
+ * struct v4l2_capability - Describes V4L2 device caps returned by
VIDIOC_QUERYCAP
+ *
+ * @driver: name of the driver module (e.g. "bttv")
+ * @card: name of the card (e.g. "Hauppauge WinTV")
+ * @bus_info: name of the bus (e.g. "PCI:" + pci_name(pci_dev) )
+ * @version: KERNEL_VERSION
+ * @capabilities: capabilities of the physical device as a whole
+ * @device_caps: capabilities accessed via this particular device (node)
+ * @reserved: reserved fields for future extensions
+ */
struct v4l2_capability {
- __u8 driver[16]; /* i.e. "bttv" */
- __u8 card[32]; /* i.e. "Hauppauge WinTV" */
- __u8 bus_info[32]; /* "PCI:" + pci_name(pci_dev) */
- __u32 version; /* should use KERNEL_VERSION() */
- __u32 capabilities; /* Device capabilities */
- __u32 reserved[4];
+ __u8 driver[16];
+ __u8 card[32];
+ __u8 bus_info[32];
+ __u32 version;
+ __u32 capabilities;
+ __u32 device_caps;
+ __u32 reserved[3];
};
/* Values for 'capabilities' field */
@@ -274,6 +283,8 @@ struct v4l2_capability {
#define V4L2_CAP_ASYNCIO 0x02000000 /* async I/O */
#define V4L2_CAP_STREAMING 0x04000000 /* streaming I/O ioctls */
+#define V4L2_CAP_DEVICE_CAPS 0x80000000 /* sets device
capabilities field */
+
/*
* V I D E O I M A G E F O R M A T
*/
--
1.7.7.3
--
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