Hi Hans, Thanks for the comments! On Fri, Nov 16, 2012 at 02:51:29PM +0100, Hans Verkuil wrote: > On Thu November 15 2012 23:06:44 Sakari Ailus wrote: > > diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml > > index 7e2f3d7..d598f2c 100644 > > --- a/Documentation/DocBook/media/v4l/io.xml > > +++ b/Documentation/DocBook/media/v4l/io.xml > > @@ -938,6 +938,31 @@ Typically applications shall use this flag for output buffers if the data > > in this buffer has not been created by the CPU but by some DMA-capable unit, > > in which case caches have not been used.</entry> > > </row> > > + <row> > > + <entry><constant>V4L2_BUF_FLAG_TIMESTAMP_MASK</constant></entry> > > + <entry>0xe000</entry> > > + <entry>Mask for timestamp types below. To test the > > + timestamp type, mask out bits not belonging to timestamp > > + type by performing a logical and operation with buffer > > + flags and timestamp mask.</tt> </entry> > > + </row> > > + <row> > > + <entry><constant>V4L2_BUF_FLAG_TIMESTAMP_UNKNOWN</constant></entry> > > + <entry>0x0000</entry> > > + <entry>Unknown timestamp type. This type is used by > > + drivers before Linux 3.8 and may be either monotonic (see > > + below) or realtime. Monotonic clock has been favoured in > > + embedded systems whereas most of the drivers use the > > + realtime clock.</entry> > > Isn't 'wallclock time' a better expression? It is probably a good idea as > well to add the userspace call that gives the same clock: gettimeofday or > clock_gettime(CLOCK_REALTIME) for the wallclock time and > clock_gettime(CLOCK_MONOTONIC) for the monotonic time. That way apps can > do the same call and compare it to the timestamp received. I'll add a reference to clock_gettime() and change realtime to wall clock time. I wonder if I should also add that the unknown timestamp means either of the two, or can we allow different kinds of unknown timestamps in the future. Probably we should limit this to realtime and monotonic. -- Kind regards, Sakari Ailus e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
