On Sat, 20 Nov 2010 david.schueler@xxxxxxxxxxxxxxxxxxx wrote: > -----linux-usb-owner@xxxxxxxxxxxxxxx wrote: ----- > > >Which of these three FTDI devices is the one that's hanging? > > These two are causing problems. > > T: Bus=03 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 2 Spd=12 MxCh= 0 > T: Bus=03 Lev=01 Prnt=01 Port=01 Cnt=02 Dev#= 3 Spd=12 MxCh= 0 Okay, the two devices on bus 3. > >> Server ~ # cat /sys/kernel/debug/usb/ohci/0000\:00\:02.0/async > >> cat: /sys/kernel/debug/usb/ohci/0000:00:02.0/async: Operation not > >permitted > > > >That's very suspicious. In fact, I can't imagine how it happened. > >Does the file not have read permission? > > > >Probably the information we need is buried in that file... > Server ohci # ls -al 0000\:00\:02.0/ > total 0 > drwxr-xr-x 2 root root 0 Nov 17 20:46 . > drwxr-xr-x 4 root root 0 Nov 17 20:46 .. > -r--r--r-- 1 root root 0 Nov 17 20:46 async > -r--r--r-- 1 root root 0 Nov 17 20:46 periodic > -r--r--r-- 1 root root 0 Nov 17 20:46 registers We're going to have to dig deeper into this issue. More later... > >Here's something else you can try as well. Make sure CONFIG_USB_MON > >is enabled, and record a usbmon trace for the bus with the device > >that > >causes the hang. Instructions are in the kernel source file > >Documentation/usb/usbmon.txt. > > Okay. This is the trace while the port (Bus=03 Port=01) is already in the > "hang" state: Sorry, I should have explained before -- I need the trace to start before the hang occurs. Ideally, start the trace before plugging in the FTDI device. Then for testing, just do an open followed by a close. 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
