On Sun, 9 Sep 2012, Florian Wöhrl wrote: > Now I have a trace from my Ubuntu 10.04 system (running on a Sony Vaio FW): > > # uname -a > Linux xxxxxxx 2.6.32-33-generic #72-Ubuntu SMP Fri Jul 29 21:07:13 UTC > 2011 x86_64 GNU/Linux > > # dmesg > Sep 9 15:30:15 xxxxxxx kernel: [ 502.821293] usb 6-2: new full speed > USB device using uhci_hcd and address 4 > Sep 9 15:30:15 xxxxxxx kernel: [ 503.031315] usb 6-2: configuration #1 > chosen from 1 choice > Sep 9 15:30:15 xxxxxxx kernel: [ 503.034271] cdc_acm 6-2:1.0: ttyACM0: > USB ACM device ... > Now the interesting info - after the board was plugged in once at the > Ubuntu 10.04 system, it also worked on the 12.04 system: > > # uname -a > Linux desktop01 3.2.0-29-generic #46-Ubuntu SMP Fri Jul 27 17:03:23 UTC > 2012 x86_64 x86_64 x86_64 GNU/Linux > > # dmesg > [52550.983426] usb 1-1.2: new full-speed USB device number 11 using ehci_hcd > [52551.079516] cdc_acm 1-1.2:1.0: This device cannot do calls on its > own. It is not a modem. > [52551.079538] cdc_acm 1-1.2:1.0: ttyACM0: USB ACM device ... > On the RPi it still doesn't work out, even though usbserial and cdc_acm > are loaded: > > # uname -a > Linux raspberrypi 3.2.27+ #102 PREEMPT Sat Sep 1 01:00:50 BST 2012 > armv6l GNU/Linux > > # dmesg > [91186.375482] usb 1-1.2: new full-speed USB device number 26 using dwc_otg > [91186.455488] usb 1-1.2: device descriptor read/64, error -71 > [91186.645392] usb 1-1.2: device descriptor read/64, error -71 > [91186.835409] usb 1-1.2: new full-speed USB device number 27 using dwc_otg > [91186.915417] usb 1-1.2: device descriptor read/64, error -71 > [91187.105575] usb 1-1.2: device descriptor read/64, error -71 > [91187.295486] usb 1-1.2: new full-speed USB device number 28 using dwc_otg > [91187.715255] usb 1-1.2: device not accepting address 28, error -71 > [91187.795636] usb 1-1.2: new full-speed USB device number 29 using dwc_otg > [91188.215277] usb 1-1.2: device not accepting address 29, error -71 > [91188.215496] hub 1-1:1.0: unable to enumerate USB device on port 2 ... > But it now still works when afterwards plugging it into the 12.04 desktop. > > Any clue? I'm not that into driver development... > Is this a firmware thing? The device is powered by USB only. Why does it > work on Ubuntu 12.04 after plugging it in once on Ubuntu 10.04? Clearly the device doesn't like your RPi system. There's some sort of hardware-level incompatibility; it may even be a question of available power as Greg suggested. You should try adding a powered hub between the computer and the device, just to see if it helps. As for the desktop systems, there's no way to tell what's happening. As far as I can see, the device should work okay with both of them all the time. The only reason I can imagine for it not working with Ubuntu 12.04 is that the RPi somehow left it in a weird invalid state. But that doesn't explain why plugging it into the other computer would clear out that state. By the way, I also get the impression that what matters is the computer hardware and not the kernel version. That is, I bet if you would use a different kernel on the RPi the device would still fail, and if you would switch the kernels on the desktop machines then the behavior would follow the machine, not the kernels. 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
