On 6 April 2010 15:45, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > On Tue, 6 Apr 2010, Pedro Ribeiro wrote: > >> So does this ring a bell? I had no idea there was a difference in USB >> handling in the kernel between 32 and 64 bit! > > As far as I know, there is no difference. Certainly there's not > _supposed_ to be any difference! > > What happens if you run a 64-bit kernel with a 32-bit userspace? > > Alan Stern > > Unfortunately I don't have a spare hard disk or disk space so I can't install a 64 bit kernel with 32 bit apps - do you know of any liveCD which has this configuration? I made some progress today. I talked to the developer of the DVB-T card driver and he made me discover that this also happens with a USB pendrive when it gets mounted or unmounted. So this is probably a snd-usb-caiaq bug. But to make matters worse, now I'm not even sure if unloading ehci_hcd solves the problem - I had to reboot yesterday because I could not make the interference go away with this method. As you can see from the messages above in this thread this is becoming very confusing. So I'm going to summarize where we stand. So where is what I know FOR SURE: - this happens on two different ICH9 platforms, not only on my laptop - only with 64 bit kernel / userland - not reproducible on 32 bit kernel / userland - the interference can be caused by both the DVB card when it is operating or a pendrive when it gets mounted or unmounted (but not when reading or writing to the partition in the pendrive) - upon fresh boot, there is no interference. I unplug and replug the audio card and the interference starts And where is what I SUSPECT BUT I'M NOT SURE: - unloading and reloading the snd-usb-caiaq module triggers the interference without unplugging and replugging - unloading and reloading ehci_hcd solves the issue till the next unplug and replug of the audio card Any of the assumptions in previous posts can and should be ignored. Once again, sorry for the mess, but you can see how hard and long this is taking to debug. Regards, Pedro -- 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
