linux-toradex.git/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml, branch v3.14.3

[media] v4l2: use __u32 rather than enums in ioctl() structs

2012-05-14T11:09:02+00:00

V4L2 uses the enum type in IOCTL arguments in IOCTLs that were defined until
the use of enum was considered less than ideal. Recently Rémi Denis-Courmont
brought up the issue by proposing a patch to convert the enums to unsigned:



This sparked a long discussion where another solution to the issue was
proposed: two sets of IOCTL structures, one with __u32 and the other with
enums, and conversion code between the two:



Both approaches implement a complete solution that resolves the problem. The
first one is simple but requires assuming enums and __u32 are the same in
size (so we won't break the ABI) while the second one is more complex and
less clean but does not require making that assumption.

The issue boils down to whether enums are fundamentally different from __u32
or not, and can the former be substituted by the latter. During the
discussion it was concluded that the __u32 has the same size as enums on all
archs Linux is supported: it has not been shown that replacing those enums
in IOCTL arguments would break neither source or binary compatibility. If no
such reason is found, just replacing the enums with __u32s is the way to go.

This is what this patch does. This patch is slightly different from Remi's
first RFC (link above): it uses __u32 instead of unsigned and also changes
the arguments of VIDIOC_G_PRIORITY and VIDIOC_S_PRIORITY.

Signed-off-by: Rémi Denis-Courmont 
Signed-off-by: Sakari Ailus 
Acked-by: Hans Verkuil 
Signed-off-by: Mauro Carvalho Chehab

[media] v4l: Document integer menu controls

2012-04-10T17:51:18+00:00

Signed-off-by: Sakari Ailus 
Acked-by: Laurent Pinchart 
Signed-off-by: Mauro Carvalho Chehab

[media] Remove unneeded comments from the media API DocBook files

2011-12-11T11:16:53+00:00

This removes comment tags intended for emacs configuration from
67 files in the Media API DocBook. Such comments are not really
helpful and violate  the coding style rules.

Signed-off-by: Sylwester Nawrocki 
Signed-off-by: Mauro Carvalho Chehab

[media] videodev2.h: add V4L2_CTRL_FLAG_VOLATILE

2011-09-21T12:52:21+00:00

Add a new VOLATILE control flag that is set for volatile controls.
That way applications know whether the value of the control is volatile
(i.e. can change continuously) or not.

Until now this was an internal property, but it is useful to know in
userspace as well.

A typical use case is the gain value when autogain is on. In that case the
hardware will continuously adjust the gain based various environmental
factors.

This patch just adds and documents the flag, it's not yet used.

Signed-off-by: Hans Verkuil 
Acked-by: Hans de Goede 
Signed-off-by: Mauro Carvalho Chehab

[media] DocBook: document V4L2_CTRL_TYPE_BITMASK

2011-07-27T20:55:39+00:00

[mchehab@redhat.com: Fix a merge conflict and make compat.xml coherent with v4l2.xml]
Signed-off-by: Hans Verkuil 
Acked-by: Sakari Ailus 
Signed-off-by: Mauro Carvalho Chehab

[media] DocBook: Move all media docbook stuff into its own directory

2011-07-27T20:52:05+00:00

This patch addresses several issues pointed by Randy Dunlap
 at changeset ece722c:

- In the generated index.html file, "media" is listed first, but it
  should be listed in alphabetical order, not first.

- The generated files are (hidden) in .tmpmedia/

- The link from the top-level index.html file to "media" is to
  media/index.html, but the file is actually in .tmpmedia/media/index.html

- Please build docs with and without using "O=builddir" and test that.

- Would it be possible for media to have its own Makefile instead of
  merging into this one?

Due to the way cleandocs target works, I had to rename the media DocBook
to media_api, otherwise cleandocs would remove the /media directory.

Thanks-to: Randy Dunlap 
Signed-off-by: Mauro Carvalho Chehab