On Tue, 2022-08-30 at 17:10 +0200, Greg Kroah-Hartman wrote: > 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. I did implement kernel drivers for devices all the way back in 2020, if you remember. > 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 :( Right.
