| Message ID | 1391813548-818-2-git-send-email-sakari.ailus@iki.fi (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 02/07/2014 11:52 PM, Sakari Ailus wrote: > Timestamp buffer flags are constant at the moment. Document them so that 1) > they're always valid and 2) not changed by the drivers. This leaves room to > extend the functionality later on if needed. > > Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> > --- > Documentation/DocBook/media/v4l/io.xml | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml > index 451626f..f523725 100644 > --- a/Documentation/DocBook/media/v4l/io.xml > +++ b/Documentation/DocBook/media/v4l/io.xml > @@ -654,6 +654,14 @@ plane, are stored in struct <structname>v4l2_plane</structname> instead. > In that case, struct <structname>v4l2_buffer</structname> contains an array of > plane structures.</para> > > + <para>Buffers that have been dequeued come with timestamps. These > + timestamps can be taken from different clocks and at different part of > + the frame, depending on the driver. Please see flags in the masks > + <constant>V4L2_BUF_FLAG_TIMESTAMP_MASK</constant> and > + <constant>V4L2_BUF_FLAG_TSTAMP_SRC_MASK</constant> in <xref > + linkend="buffer-flags">. These flags are guaranteed to be always valid > + and will not be changed by the driver.</para> That's a bit too strong. Different inputs or outputs may have different timestamp sources. Also add a note that the SOE does not apply to outputs (there is no exposure there after all). For EOF the formulation for outputs should be: "..last pixel of the frame has been transmitted." For the COPY mode I think the SRC_MASK bits should be copied as well. That should be stated in the documentation. Regards, Hans > + > <table frame="none" pgwide="1" id="v4l2-buffer"> > <title>struct <structname>v4l2_buffer</structname></title> > <tgroup cols="4"> > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Hans, Thanks for the comments. Hans Verkuil wrote: > On 02/07/2014 11:52 PM, Sakari Ailus wrote: >> Timestamp buffer flags are constant at the moment. Document them so that 1) >> they're always valid and 2) not changed by the drivers. This leaves room to >> extend the functionality later on if needed. >> >> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> >> --- >> Documentation/DocBook/media/v4l/io.xml | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml >> index 451626f..f523725 100644 >> --- a/Documentation/DocBook/media/v4l/io.xml >> +++ b/Documentation/DocBook/media/v4l/io.xml >> @@ -654,6 +654,14 @@ plane, are stored in struct <structname>v4l2_plane</structname> instead. >> In that case, struct <structname>v4l2_buffer</structname> contains an array of >> plane structures.</para> >> >> + <para>Buffers that have been dequeued come with timestamps. These >> + timestamps can be taken from different clocks and at different part of >> + the frame, depending on the driver. Please see flags in the masks >> + <constant>V4L2_BUF_FLAG_TIMESTAMP_MASK</constant> and >> + <constant>V4L2_BUF_FLAG_TSTAMP_SRC_MASK</constant> in <xref >> + linkend="buffer-flags">. These flags are guaranteed to be always valid >> + and will not be changed by the driver.</para> > > That's a bit too strong. Different inputs or outputs may have different timestamp Fixed. > sources. Also add a note that the SOE does not apply to outputs (there is no The flags are already documented separately, but I can add that to make it explicit. > exposure there after all). For EOF the formulation for outputs should be: > "..last pixel of the frame has been transmitted." Added. > For the COPY mode I think the SRC_MASK bits should be copied as well. That should > be stated in the documentation. Good point. I'll make that a separate patch as it changes a number of drivers. Perhaps this could be a good occasion to clean up some timecode field usage from those drivers, too.
diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml index 451626f..f523725 100644 --- a/Documentation/DocBook/media/v4l/io.xml +++ b/Documentation/DocBook/media/v4l/io.xml @@ -654,6 +654,14 @@ plane, are stored in struct <structname>v4l2_plane</structname> instead. In that case, struct <structname>v4l2_buffer</structname> contains an array of plane structures.</para> + <para>Buffers that have been dequeued come with timestamps. These + timestamps can be taken from different clocks and at different part of + the frame, depending on the driver. Please see flags in the masks + <constant>V4L2_BUF_FLAG_TIMESTAMP_MASK</constant> and + <constant>V4L2_BUF_FLAG_TSTAMP_SRC_MASK</constant> in <xref + linkend="buffer-flags">. These flags are guaranteed to be always valid + and will not be changed by the driver.</para> + <table frame="none" pgwide="1" id="v4l2-buffer"> <title>struct <structname>v4l2_buffer</structname></title> <tgroup cols="4">
Timestamp buffer flags are constant at the moment. Document them so that 1) they're always valid and 2) not changed by the drivers. This leaves room to extend the functionality later on if needed. Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> --- Documentation/DocBook/media/v4l/io.xml | 8 ++++++++ 1 file changed, 8 insertions(+)