> In an earlier message I wrote that the HC driver couldn't unload so long > as the device usbfs was using held a reference to its bus. I just did > some checking, and guess what: It can!
Uh oh. > I looked at both the UHCI and OHCI drivers. In their module_exit routines > they call pci_unregister_driver(). Without knowing how the PCI subsystem > works, I would assume this behaves like any other "deregister" routine in > the driver model and returns without waiting for any reference count to go > to 0 -- that's what release callbacks are for. > > However, the module_exit routines _don't_ wait for the release callbacks. > They just go right on ahead and exit. Result: when the reference count > eventually does go to 0 (when usbfs drops its last reference), the > hcd_free routine is no longer present and you get an oops. > > The proper fix would be to have each HC driver keep track of how many > instances are allocated. The module_exit routine must wait for that > number to drop to 0 before returning. Is this how it is usually done? All the best, Duncan. ------------------------------------------------------- This SF.net email is sponsored by: IBM Linux Tutorials. Become an expert in LINUX or just sharpen your skills. Sign up for IBM's Free Linux Tutorials. Learn everything from the bash shell to sys admin. Click now! http://ads.osdn.com/?ad_id=1278&alloc_id=3371&op=click _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
