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| author | Hans Verkuil <hans.verkuil@cisco.com> | 2012-09-03 14:37:18 +0200 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2012-09-26 14:30:22 +0200 |
| commit | 93828d6438081649e81b8681df9bf6ad5d691650 (patch) | |
| tree | 0529d43509c1782b3e2f88a896e4540f408c2e87 /Documentation/DocBook | |
| parent | [media] DocBook: improve STREAMON/OFF documentation (diff) | |
| download | linux-93828d6438081649e81b8681df9bf6ad5d691650.tar.xz linux-93828d6438081649e81b8681df9bf6ad5d691650.zip | |
[media] DocBook: make the G/S/TRY_FMT specification more strict
- S/TRY_FMT should always succeed, unless an invalid type field is passed in.
- TRY_FMT should give the same result as S_FMT, all other things being equal.
- ENUMFMT may return different formats for different inputs or outputs.
This was decided during the 2012 Media Workshop.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/DocBook')
| -rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-enum-fmt.xml | 3 | ||||
| -rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-g-fmt.xml | 9 |
2 files changed, 9 insertions, 3 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-enum-fmt.xml b/Documentation/DocBook/media/v4l/vidioc-enum-fmt.xml index 81ebe48317fe..0bd332421407 100644 --- a/Documentation/DocBook/media/v4l/vidioc-enum-fmt.xml +++ b/Documentation/DocBook/media/v4l/vidioc-enum-fmt.xml @@ -58,6 +58,9 @@ structure. Drivers fill the rest of the structure or return an incrementing by one until <errorcode>EINVAL</errorcode> is returned.</para> + <para>Note that after switching input or output the list of enumerated image +formats may be different.</para> + <table pgwide="1" frame="none" id="v4l2-fmtdesc"> <title>struct <structname>v4l2_fmtdesc</structname></title> <tgroup cols="3"> diff --git a/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml b/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml index 52acff193a6f..b4b0e0a28545 100644 --- a/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml +++ b/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml @@ -81,7 +81,7 @@ the application calls the <constant>VIDIOC_S_FMT</constant> ioctl with a pointer to a <structname>v4l2_format</structname> structure the driver checks and adjusts the parameters against hardware abilities. Drivers -should not return an error code unless the input is ambiguous, this is +should not return an error code unless the <structfield>type</structfield> field is invalid, this is a mechanism to fathom device capabilities and to approach parameters acceptable for both the application and driver. On success the driver may program the hardware, allocate resources and generally prepare for @@ -107,6 +107,10 @@ disabling I/O or possibly time consuming hardware preparations. Although strongly recommended drivers are not required to implement this ioctl.</para> + <para>The format as returned by <constant>VIDIOC_TRY_FMT</constant> +must be identical to what <constant>VIDIOC_S_FMT</constant> returns for +the same input or output.</para> + <table pgwide="1" frame="none" id="v4l2-format"> <title>struct <structname>v4l2_format</structname></title> <tgroup cols="4"> @@ -187,8 +191,7 @@ capture and output devices.</entry> <term><errorcode>EINVAL</errorcode></term> <listitem> <para>The &v4l2-format; <structfield>type</structfield> -field is invalid, the requested buffer type not supported, or the -format is not supported with this buffer type.</para> +field is invalid or the requested buffer type not supported.</para> </listitem> </varlistentry> </variablelist> |