On Tue, Aug 30, 2022 at 04:44:52PM +0200, Bastien Nocera wrote: > On Thu, 2022-08-18 at 17:08 +0200, Greg Kroah-Hartman wrote: > > On Tue, Aug 09, 2022 at 07:27:11PM +0200, Bastien Nocera wrote: > > > On Tue, 2022-08-09 at 18:33 +0200, Greg Kroah-Hartman wrote: > > > > On Tue, Aug 09, 2022 at 04:31:04PM +0200, Bastien Nocera wrote: > > > > > On Tue, 2022-08-09 at 12:38 +0200, Greg Kroah-Hartman wrote: > > > > > > Now if you really really want to disable a device from under > > > > > > a > > > > > > user, > > > > > > without the file handle present, you can do that today, as > > > > > > root, > > > > > > by > > > > > > doing the 'unbind' hack through userspace and sysfs. It's so > > > > > > common > > > > > > that this seems to be how virtual device managers handle > > > > > > virtual > > > > > > machines, so it should be well tested by now. > > > > > > > > > > The only thing I know that works that way is usbip, and it > > > > > requires > > > > > unbinding each of the interfaces: > > > > > > > > > > https://sourceforge.net/p/usbip/git-windows/ci/master/tree/trunk/userspace/src/bind-driver.c#l157 > > > > > > > > virtio devices also use the api from what I recall. > > > > > > I can't find any code that would reference > > > /sys/bus/usb/drivers/usbfs/unbind or /sys/bus/usb/drivers/usbfs wrt > > > virtio. Where's the host side code for that? > > > > I mean the virtio code uses bind/unbind for it's devices, nothing to > > do > > with USB other than the userspace interface involved. > > This is one big hammer that is really counterproductive in some fairly > common use cases. It's fine for assigning a full USB device to a VM, it > really isn't for gently removing "just that bit of interface" the user > is using while leaving the rest running. In USB, drivers are bound to interfaces, not to the device. But as Alan pointed out, we don't ever really "bind" the usbfs code to the interface, so that will not work all that well :( greg k-h
