On Thu, Dec 20, 2007 at 06:43:23PM +0100, Oliver Neukum wrote: > Am Donnerstag, 20. Dezember 2007 17:37:49 schrieb Greg KH: > > On Thu, Dec 20, 2007 at 10:32:50AM -0500, Alan Stern wrote: > > > On Thu, 20 Dec 2007, Oliver Neukum wrote: > > > > > > > Hi, > > > > > > > > the mos7720 driver sends two commands to the device whenever it is > > > > closed. It does so unconditionally even if the device has been > > > > disconnected. > > > > It seems to me that this is wrong. Making sure that this does not happen > > > > for disconnected devices takes a bit of infrastructure in the generic > > > > part. > > > > However I am not sure whether this interfeeres with hanging up the tty. > > > > What do you think? > > > > > > There's nothing wrong with trying to send those commands if the device > > > really is disconnected. The attempts will fail quickly. > > > > > > The problem arises when the device is still connected but the driver > > > has been unbound. That is illegal; a driver is never supposed to > > > access a device once its unbind method has returned. > > > > > > Do other serial drivers suffer from a similar problem? > > > > The io_edgeport-like devices all want to send a "flush" type command > > when they are closed, and it doesn't look like they check for disconnect > > either :( > > From a more general angle, perhaps what we provide with usb_kill_urb() > is not ideally suited to combat this problem. What about a construction like > this:
That's nice, but it will not solve the issue with devices like the io-edgeport, which sends a new control message to the device from what I remember. Or it will not work for any device that creates new urbs for every message, a model drivers are moving more toward over time... thanks, greg k-h - To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
