On Thu, 2006-04-13 at 00:37 +0200, Guennadi Liakhovetski wrote: > On Wed, 12 Apr 2006, Greg KH wrote: > > > > Problem 3. Recursive error-messages on dongle-unplug, which render the > > > system unusable. Here again, the proper solution would be to implement > > > some usb_serial_console_disconnect() which would prevent sending output > > > to > > > a disconnected port. A possible implementation is also included below. > > > Paul had a different version, whereby he was calling > > > unregister_console(), > > > which I was not sure about. Anyway, none of these disconnect() > > > implementations alone suffice to fix the problem. What indeed fixes it is > > > a check for (port->serial->dev->state == USB_STATE_NOTATTACHED) in > > > usb_console_write(). Just in case the same check was added to > > > serial_write() in drivers/usb/serial/usb-serial.c. > > > > > > Hm, usb_serial_console_disconnect() is probably the proper way to do > > this.
We probably need both. Checking the device state on console write is necessary to prevent lockup on console write. I'm assuming there is some kind of recursion problem, but the lock could be something else. usb_serial_console_disconnect() cleans up so there is not a stale port pointer hanging around that is part of a now invalid console registration. CPU cycles are saved by not having the console subsystem constantly trying to write to a device that is not there. -- Paul ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642 _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
