On Friday 18 August 2006 12:04 pm, Alan Stern wrote: > On Fri, 18 Aug 2006, Clemens Ladisch wrote: > > > Alan Stern wrote: > > > On Fri, 18 Aug 2006, Clemens Ladisch wrote: > > > > It usually does put more than one packet into each URB, except when > > > > an application requests interrupts at a higher rate, or when the > > > > nrpacks module parameter is set to a lower value. > > > > > > > > The output from speaker-test indicates that it sets the period size > > > > to 64 KB (i.e., interrupts every 341 frames), so I guess that > > > > nrpacks is set to 1. > > > > > > Yes, it was. I see the default value is 4 and the max is 10. Could > > > those values be increased? > > > > Yes, easily. The driver itself doesn't have any inherent upper limit. > > > > However, increasing the number of scheduled packets will increase the > > audio latency. I wouldn't want to have the default be more than > > 100 ms or so. > > > > I'll increase the defaults. > > Thanks. Something like a default of 10 - 15 and a max of 30 - 50 > should be good.
The advice for ISO transfers with EHCI is that even 64 msec per URB is likely to cause trouble, so use less; and the total queue depth should be no more than about 230 msec total. See comment in ehci_sched.c at the top of iso_stream_schedule(). Not sure how that applies to numbers like 10-15 or 30-50, or even 4-10. - Dave ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
