Re: [Libusb-devel] libusb silently ignores permission errors
Alan Stern <[email protected]>
| Newsgroups | gmane.linux.usb.devel |
|---|---|
| Message-ID | <[email protected]> |
On Sun, 23 Sep 2007, Xiaofan Chen wrote: > > Try building a kernel with CONFIG_USB_SUSPEND disabled. > > > > Ah this is the key. Now it is ok, I believe the firmware does not adequately > handle USB suspend. I am still investigating how to handle USB suspend > correctly by changing the Microchip provided firmware framework. > http://forum.microchip.com/tm.aspx?m=275422 > > Could you explain what happend to lsusb why it failed to find the device in > the case that CONFIG_USB_SUSPEND is enabled? Thanks in advance. After you plugged in the device, the kernel suspended it. Then when you ran lsusb, the kernel tried to unsuspend the device -- but instead of resuming correctly, the device disconnected itself. (Maybe as part of the firmware's resume sequence, it removed the D+ pullup resistance.) Hence lsusb wasn't able to find it. Shortly afterward, the device connected itself again. Alan Stern ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel