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. -- Chase -- 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
