On 6 April 2010 23:05, Pedro Ribeiro <pedrib@xxxxxxxxx> wrote: > 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 > Good news: I've talked to the snd-usb-caiaq developer and he gave me a patch which appears to solve the problem. I'm going to test it for a couple of days just to make sure before I OK him. 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
