On Thu, 18 Mar 2010, Pedro Ribeiro wrote: > After much research I found the culprit - apparently if I rmmod and > modprobe the ehci_usb device the interference is gone without having > to fresh boot (of course before this I unload the modules for the dvb > and audio devices). > > I was to able to reproduce this problem in kernels 2.6.31 to 2.6.33 (I > haven't tried any others). I WAS NOT able to reproduce on a ICH4 > laptop I have. > > The DVB-T adapter uses the dvb_usb_dib0700 module and the audio card > uses the snd-usb-caiaq module. It's hard to say what could be causing the problem here. The best approach I can think of is to collect a pair of usbmon traces: one while the problem occurs and one while everything works correctly. (See the kernel source file Documentation/usb/usbmon.txt for instructions.) Attach the two traces to the bug report. They don't have to be very long; just enough to cover some occurrences of the sound interference. Also, you should attach a dmesg log (with CONFIG_USB_DEBUG enabled) showing what happens when you unload and reload ehci-hcd, and what happens when you unplug and replug the audio card. Does the same problem occur if you unload and reload the audio driver instead of unplugging and replugging the audio card? 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
