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? > (I've heard that using nrpacks=1 is a way to trigger those > incorrect bandwidth warnings.) Well, almost anything you do with iso transactions will trigger those warnings in uhci-hcd. The bandwidth reservation code is completely broken. That's going to be one of the next things I fix. In the latest test in that bug report (attached to comment #20) I found what appears to be a bug in snd-usb-audio. Here's an extract from the usbmon log: d687f520 993504083 S Zo:002:06 -115 192 = df3fdf3f 893f893f fd3efd3e d687f5a0 993505076 C Zo:002:06 0 192 > d687f5a0 993505126 S Zo:002:06 -115 192 = 21c321c3 18c218c2 43c143c1 d687f620 993506078 C Zo:002:06 -104 192 > d687f6a0 993506084 C Zo:002:06 -104 0 d687f120 993506088 C Zo:002:06 -104 0 d687f1a0 993506093 C Zo:002:06 -104 0 d687f220 993506097 C Zo:002:06 -104 0 d687f2a0 993506101 C Zo:002:06 -104 0 d687f520 993506105 C Zo:002:06 -104 0 d687f5a0 993513075 C Zo:002:06 0 192 > d687f120 993514134 S Zo:002:06 -115 192 = 00000000 00000000 00000000 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. Anyway, the driver always has eight URBs queued. The URB at d687f5a0 was the last one submitted before everything was cancelled. The driver unlinked 7 of the 8 URBs, but the last one was left to complete normally, 8 ms after it was submitted. That looks like an off-by-one error in the cancellation code. 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
