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[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>
This commit is contained in:
Hans Verkuil 2012-01-11 06:45:05 -03:00 committed by Mauro Carvalho Chehab
parent 93596ef7db
commit 583aa3a9b5
7 changed files with 69 additions and 17 deletions

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@ -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>

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@ -127,6 +127,13 @@ structs, ioctls) must be noted in more detail in the history chapter
(compat.xml), along with the possible impact on existing drivers and
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>
@ -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;

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@ -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>

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@ -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)

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@ -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 [] = {

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@ -540,10 +540,12 @@ 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;
}

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@ -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
*/