Hi Sakari, On Friday 09 November 2012 00:33:40 Sakari Ailus wrote: > On Thu, Nov 08, 2012 at 01:18:15PM +0100, Laurent Pinchart wrote: > > 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. > > The vb2 already stores struct v4l2_buffer, but unfortunately driver's > queue_setup() is called before alloctaing buffer objects, or after if less > buffers can be allocated that way. > > The information could be stored in the buffer queue itself. That'd likely > make it the easies for the drivers: otherwise drivers need to be involed > e.g. in querybuf. > > What do you think? I don't foresee any need for per-buffer timestamps for now, so I would be fine with a per-queue flag. -- 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
