On Mon, 13 Sep 2010, Jiri Slaby wrote: > On 09/13/2010 04:48 PM, Alan Stern wrote: > > On Mon, 13 Sep 2010, Jiri Slaby wrote: > >> In other words, what I could do is to add some printks into > >> hub_port_connect_change if that's called at all. If you need some > >> thorough debugging printks, please send me a patch to test instead. > > > > Hmm. I'd prefer to explain how it's all supposed to work and let you > > figure out where best to look. Or try to debug it myself. Does this > > happen with other sorts of USB devices as well, or just wacom? > > With some sort of devices (I cannot reproduce myself). It's unrelated to > wacom -- people with wacom were unable to even start X with this kernel. > If you look at the bugreport, there are several examples: > ID 046d:c517 Logitech, Inc. LX710 Cordless Desktop Laser defunct > Microsoft USB keyboard defunct x Logitech mice OK > 046a:0021 Cherry GmbH keyboard defunct > logitech wireless laptop mouse defunct > A$Tech wireless laptop mouse defunct > TypeMatrix USB 2030 (ID : 1e54:2030) defunct Okay, I see the problem. By moving usb_detect_quirks earlier, we end up calling usb_disable_autosuspend too soon -- before the pm_runtime_enable call in usb_new_device. In 2.6.35 this doesn't matter because the implementation of usb_autosuspend_device has changed. So yes, in the end it looks like the best course is to revert this patch from 2.6.34.stable. This is unfortunate but I don't see any way around it without making changes that aren't present in the current kernel. For example, the pm_runtime_set_active and pm_runtime_enable calls could also be moved from usb_new_device into hub_port_connect_change. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
