On Sun, Sep 9, 2012 at 6:04 AM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > On Sat, 8 Sep 2012, Florian Wöhrl wrote: >> I first thought it might be the change in the driver - because in the >> past 04d8:000a was handled by cdc_acm, now the modalias shows ftdi_sio. > > No, that can't be the reason. The problem occurs before the driver is > loaded. And I do not think ftdi_sio should be loaded for this device since it is really not an FTDI device after all. 04d8:000a is a CDC-ACM demo device from Microchip's USB Firmware Framework. >> But I had contact with Oliver Neukum, the maintainer of cdc_acm. He told >> me to contact this mailing list as he thinks it is a problem in usbcore. > > I don't think the problem is in the core. Certainly those -71 errors > in your usbmon trace are caused by hardware or firmware issues, not by > software. > >> yes, the device is working perfectly under Windows (7) and in Ubuntu >> 10.04 with kernel 2.6.+. >> The cdc_acm driver is loaded and a device /dev/ttyACM0 is created. >> But starting with kernel 3.2.+ - as in Ubuntu 12.04 or Debian Wheezy - >> the descriptors cannot be read. > > Do you mean that the descriptors cannot be read when running Ubuntu > 12.04 on a desktop system? The earlier version of the firmware has some serious bugs, one of them is with regard to suspend/resume. The other problem is in handling of data toggle. Could this problem be related to these firmware bugs? I do not think so but just want to mention the possibility of firmware bugs. -- Xiaofan -- 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
