Hi Sakari, On Monday 05 November 2012 16:04:32 Sakari Ailus wrote: > On Sun, Nov 04, 2012 at 01:07:25PM +0100, Laurent Pinchart wrote: > > On Wednesday 24 October 2012 21:16:23 Sakari Ailus wrote: > ... > > > > @@ -367,7 +368,8 @@ static void __fill_v4l2_buffer(struct vb2_buffer > > > *vb, > > > struct v4l2_buffer *b) /* > > > > > > * Clear any buffer state related flags. > > > */ > > > > > > - b->flags &= ~V4L2_BUFFER_STATE_FLAGS; > > > + b->flags &= ~V4L2_BUFFER_MASK_FLAGS; > > > + b->flags |= V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC; > > > > That's an issue. Drivers that use videobuf2 would always be restricted to > > monotonic timestamps in the future, even if they provide support for a > > device- specific clock. > > > > Would it instead make sense to pass a v4l2_buffer pointer to > > v4l2_get_timestamp() and set the monotonic flag there ? Not all callers of > > v4l2_get_timestamp() might have a v4l2_buffer pointer though. > > For now, this patch assumes that all the VB2 users will use monotonic > timestamps only. Once we have a good use case for different kind of > timestamps and have agreed how to implement them, I was thinking of adding a > similar function to v4l2_get_timestamp() but which would be VB2-aware, with > one argument being the timestamp type. That function could then get the > timestamp and apply the relevant flags. > > Do you think it'd be enough to support changeable timestamp type for drivers > using VB2 only? Given that there's no reason to use anything else than VB2 in V4L2 drivers, I don't see any problem there. How would that work in practice ? You won't be able to override the timestamp type flag unconditionally in __fill_v4l2_buffer() anymore. > Alternatively we could make v4l2_get_timestamp() v4l2_buffer-aware, and for > drivers that can't provide the buffer pointer we could just set the pointer > to NULL, and v4l2_get_timestamp() could ignore it. The driver would then be > responsible for setting the right flags to the buffer on its own. As far as > I understand, this is essentially what you proposed. -- Regards, Laurent Pinchart -- 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
