On Tue, 2015-01-20 at 18:58 +0400, Kirill Elagin wrote: > On Tue, Jan 20, 2015 at 5:06 PM, Oliver Neukum <oneukum@xxxxxxx> wrote: > > On Tue, 2015-01-20 at 16:18 +0400, Kirill Elagin wrote: > >> I use a Logitech wireless keyboard (with a Unifying receiver) and it > >> keeps working fine even with `auto`. > >> > >> That is, everything is OK if the receiver is plugged before > >> `power/control` is switched to `auto`. > > > > Wait. There is no power/control file for the receiver before > > you plug it in. We are having a very big misunderstanding here. > > Sorry for not being clear. I was referring to `power/control` of the > USB-device itself except for the cases when I was talking about > hot-plugging issues — in those cases I was referring to the > `power/control` of the root hub. Please check whether you are not accidentally touching the ports linux-0dmf:/sys/bus/usb/devices/usb1/1-0:1.0/usb1-port1 At paths like this you find control files for ports, not the root hub as a device. > In this particular case I was talking about the `power/control` of the root hub. OK, so autosuspend does work if you enable it for the device but not the hub? > `laptop-mode-tools` by default writes `auto` to `power/control` of > _all_ the USB devices, root hubs included (even when on AC). Is it > really expected that kernel might completely power off the physical > USB port? Sounds weird. It can. It is a recent feature if ACPI supports that on a machine. > Here is an even more strange thing. First I set all the USB power > management to the defaults (that is, `auto` for all the usb devices > including root hubs). Again, the keyboard keeps working and as soon as > I unplug the receiver kernel says the device was disconnected. Now if > I plug the receiver back nothing happens. _But_ if I plug a flash > drive in the save physical port it gets detected. So, I tried a number > of other usb devices and it totally looks like USB2.0 ones are > properly hot-plugged while USB1.1 devices are not. Does this sound to > you like a bug in my laptop's hardware? Could be, but could also be software. Please double check where exactly an "on" is needed. 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
