On 11/05/15 09:36, Arnd Bergmann wrote: > On Thursday 05 November 2015 08:41:11 Hans Verkuil wrote: >> Hi Arnd, >> >> We're redesigning the timestamp handling in the video4linux subsystem moving away >> from struct timeval to a single timestamp in ns (what ktime_get_ns() gives us). >> But I was wondering: ktime_get_ns() gives a s64, so should we use s64 as well as >> the timestamp type we'll eventually be returning to the user, or should we use u64? >> >> The current patch series we made uses a u64, but I am now beginning to doubt that >> decision. > > I would lean towards u64, but I don't think it really matters either way, > especially since all the drivers should be using monotonic timestamps now. One thing that might be easier if it is a s64 is when adding/subtracting offsets from the timestamp. And the other reason is that a u64 gives a false view of the underlying type. With a s64 it is clear that a timestamp will wrap around after 292 years instead of double that. Admittedly, not our problem, but if we ever send a space probe to Alpha Centauri, then it might be nice to know as application developer that you need to take special measures if the mission takes longer than 292 years :-) Regards, Hans -- 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
