On Sat, 3 Mar 2007, Laurent Pinchart wrote: > Hi everybody, > > I'm trying to find a way to synchronise the Linux system clock with a device > clock using the USB frame counter as a shared clock. ... > I end up with three time sources: the device clock, the USB clock (through > the > SOF counter), and the Linux system clock. The jitter between the device clock > and the USB clock is reported in the Source Clock Reference, and the jitter > between the USB clock and the Linux system clock should be computed somehow. > I then need to use all those parameters to estimate the jitter between the > device clock and the Linux system clock, to convert the PTS values into Linux > system clock units. > > I'd like to know if anyone has ever solved the same problem, or thought about > how to solve it. I know there's a way to retrieve the current SOF counter, > but there doesn't seem to be a way to get the Linux system clock at the time > the SOF packet is sent. > > Any help would be appreciated.
Section 5.12 of the USB 2.0 spec contains an extensive discussion of clock synchronization. Alan Stern ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
