On Mon, 26 Dec 2005, Dmitry Torokhov wrote: > On Monday 26 December 2005 16:20, Patrick Mochel wrote: > > > > Unbinding and > > > > rebinding do a whole lot more. A device does an entire round trip through > > > > the driver core, which does a lot of crap. There are several memory > > > > allocations, perhaps dozens of sysfs files created, and a handful of locks > > > > taken adn lists traversed. > > > > > > No, you're thinking of unregistering and re-registering a device or > > > driver. Unbinding and rebinding is much simpler, although still somewhat > > > complex. > > > > Ah, point taken; I was thinking that all USB devices were still > > disconnected during a suspend transition.. > > > > Device removal could happen at any point, even during suspend transition. > The kernel should be able to handle this scenario therefore implementation > that assumes that device tree is frozen in flawed. As far as I understand > the only thing that does not work at the moment is invoking hotplug handler. I don't think that the tree should be assumed to be frozen. I just think that we should try to avoid doing a full add or remove of a device (or really, any object) while in a suspend or resume transition. During normal system operation, how does a USB device get removed? Does it happen via the USB hub thread? Forgive me for asking a question that's probably been asked countless times, but is this thread running during a suspend transition? Would it be possible to simply mark the device as 'removed' and ignore it until we resumed, and then clean it up (hotplug events and everything)? Thanks, Patrick
