On Thu, Jan 05, 2012 at 04:37:00PM -0800, Chase Douglas wrote: > On 01/05/2012 04:19 PM, John Stultz wrote: > > On Thu, 2012-01-05 at 15:54 -0800, Chase Douglas wrote: > >> On 01/05/2012 03:28 PM, Dmitry Torokhov wrote: > >>> Hi John, > >>> > >>> On Thu, Jan 05, 2012 at 03:01:05PM -0800, John Stultz wrote: > >>>> > >>>> + case EVIOCMONTIME: > >>>> + if (copy_from_user(&i, p, sizeof(unsigned int))) > >>>> + return -EFAULT; > >>>> + client->use_monotonic = i; > >>>> + return 0; > >>> > >>> Maybe we should let users pass not boolean but CLOCK_* value (and reject > >>> ones that we do not support) ? This way if someone wants to use some > >>> other clock type in the future we won't need new ioctl. > >> > >> Could we also find a way to specify device time? Apple's Magic Mouse and > >> Magic Trackpad spit out events with their own timestamps. Maybe there > >> would be other devices that would support high accuracy timestamps too? > > > > The dynamic posix clocks stuff already supports this sort of thing for > > PTP, but its driver by driver, and its not all that clear that you can > > read the device timestamp any old time you want (I suspect they're all > > tied to device events). So it won't quite work for a clock_gettime() > > style usage. > > > > I don't really know what the best way to do this would be. We could > > overload a negative clockid value, since you're not going to be wanting > > thread cputime for device timestamps. But that's not super elegant > > either. > > > > But just having a specified clock id via the ioctl makes something like > > what you're proposing possible. Just a matter of how to cleanly specify > > device timestamps against all the other possible ids. > > I guess this is mostly what I'm after right now. I have no plans on > implementing device timestamps, and I don't even really have time to > think about it much right now :). As long as we have a plan for how we > could specify it in the future, if someone wanted to implement it, then > I'm happy. > I'd consider device-generated timestamps be similar to the other elements of input stream, like coordinates, and therefore transmitted via their own event type, something like EV_MSC/MSC_TIME. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
