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. > > As far as I can tell, something caused the driver to cancel its > > ongoing activity and restart. Maybe the test program closed the > > device file and re-opened it. > > I'd guess the stream was stopped due to an underrun, i.e., the > application didn't fill the buffer fast enough. This shouldn't happen > with speaker-test except when something else eats too much CPU. I don't know what else was running at the time -- probably not too much. On the other hand, the USB controller was reporting all those PCI underruns, so something weird was happening. Hard to tell whether it was in the software or the hardware. Alan Stern ------------------------------------------------------------------------- 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
