On Fri, 26 Jun 2015, Greg Kroah-Hartman wrote: > > This doesn't do what the patch title says. USB_DEVICE_FIXED means that > > the device can't be unplugged from its upstream port. It doesn't mean > > the device is internal to the computer. > > > > As an example, consider a composite Apple keyboard, which has an > > internal 3-port USB hub where two of the hub's ports are exposed on the > > edge of the keyboard case and the keyboard controller is permanently > > attached to the third hub port. Then the controller device would be > > marked USB_DEVICE_FIXED, even though the whole thing is external to > > the computer and can be unplugged. > > > > Is that really how those devices are marked? I can't find any of my > keyboard with hubs that mark things that way. My Apple keyboard isn't here at the moment, and I don't remember exactly what its hub descriptor contains. In theory, it _should_ mark the permanently attached port as non-removable. I can test it next week, if you would like to see the actual values. > > Also, are you really certain this is safe? Aren't there a number of > > built-in keyboards that will work badly if you allow them to > > autosuspend? > > udev has been doing this for a while now by default, with no reports of > problems, so I think we should be safe. I thought udev used a whitelist of devices known to work okay with autosuspend. Does it really turn on autosuspend for _every_ USB HID device that is marked as removable? (Come to think of it, given the bug in the hub driver, no device attached directly to the root hub will _ever_ be marked as removable AFAICS. So maybe that bug is masking possible regressions.) 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
