On Mon, 18 Feb 2013, Stefan Tauner wrote: > This allows user space to retrieve the current frame number on a USB > as returned by usb_get_current_frame_number(...) via sysfs. > > Signed-off-by: Stefan Tauner <stefan.tauner@xxxxxxxxxxxxxxxxxxxx> > --- > That's sadly not necessarily the raw value seen on the bus because > the individual driver functions called by usb_get_current_frame_number(...) > seem to limit the possible range to the "schedule horizon" of isochronous > packets. IMHO the function name is a misnomer and I would like to hear your > opinion on this, a possible new name for it and a better way to retrieve the > real/raw value. A problem, as you point out, is that the individual host controller drivers are somewhat careless about how they implement this. For example, the value reported by ehci-hcd increments 125 us before the value seen on the bus (in addition to being limited to the "schedule horizon" for no good reason). Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
