On Fri, 2014-03-07 at 10:14 -0500, Alan Stern wrote: > On Fri, 7 Mar 2014, Oliver Neukum wrote: > > > > Are there any wakeup-enabled devices that this will mess up? > > > > Potentially HID. Now that I think about this it seems to me that > > drivers really need to be told about the error condition. For > > btusb the error condition cannot be handled. For HID it may mean > > a lost key or click at the worst. The driver should react to such > > errors by disabling power management, but that requires that it > > become aware of such errors. > > The only way to notify the driver about the error condition is by a > reset-resume callback, and btusb has no such callback. I wouldn't object to adding reset_resume() provided you add an error flag and usbcore can deal with a failure. > In the case of a mobile device, it seems to me that unbinding and > rebinding is more suitable than disabling power management. > Especially if these errors are infrequent. It breaks opened fds. > Of course, unbind followed by rebind is a natural side effect of > logical disconnect. > > Earlier, you objected to rebinding on the grounds that it could lead to > a tight error loop. Unbinding without rebinding would be essentially > the same as what the kernel does now. Yes, I much prefer drivers to be notified. Regards Oliver -- 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
