On Tue, Jun 14, 2022 at 3:06 AM Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> wrote: > > On 9.6.2022 18.08, Evan Green wrote: > > On Thu, Jun 9, 2022 at 12:58 AM Mathias Nyman > > <mathias.nyman@xxxxxxxxxxxxxxx> wrote: > >> > >> On 8.6.2022 16.43, Alan Stern wrote: > >>> On Wed, Jun 08, 2022 at 02:47:22PM +0300, Mathias Nyman wrote: > >>>> On 8.6.2022 11.19, Oliver Neukum wrote: > >>>>> > >>>>> > >>>>> On 07.06.22 15:58, Mathias Nyman wrote: > >>>>> > >>>>> Hi, > >>>>> > >>>>>> In shutdown (S5), with xHCI as host, this can be solved fairly easily > >>>>>> by turning off roothub port power in the .shutdown path. > >>>>> > >>>>> That would suck for the people who charge their phone from their > >>>>> computer. > >>>> > >>>> Good point. > >>>> My guess is that xHC port power bits won't actually turn off VBus for those > >>>> Sleep-and-charge, or Always-on ports. > >>>> VBus is allowed to be on even if port is in power-off state, but usb link state > >>>> should be forced to ss.Disabled from other states, like U3. > >>>> > >>>> Need to try it out, it's possible this turns off VBus for some usb-A ports > >>>> on some older systems that earlier (accidentally?) supplied VBus on > >>>> "normal" ports after shutdown. > >>> > >>> How about turning off port power _only_ in the shutdown or unbind path, > >>> and setting the port link states to ss.Disabled in the poweroff or > >>> poweroff_noirq stage of hibernation (if wakeup is disabled)? Would that > >>> solve the problem of the firmware needing to time out on reboot? > >>> > >> > >> That would be optimal, but unfortunately xHCI doesn't support setting link > >> state directly to ss.Disabled. Only way is to clear port power (PP) bit. > >> > >> To avoid turning off VBus in hibernate we could limit port power bit clearing > >> to xHC hosts that don't have the Port Power Control (PPC) capability flag. > >> > >> We know these xHC hosts don't control power switches, and clearing PP won't turn > >> off VBus (xhci 5.4.8, PORTRSC) > >> > >> This could be a solution for some hosts, but probably not cover all. > >> Not sure if the hardware this was reported on has PPC flag set. > > > > It appears it does not, HCCPARAMS1 for both USB controllers seems to > > be 0x20007fc1 (missing bit 3). You can check my work in case I made an > > error here: https://pastebin.com/9raZc63N > > -Evan > > Thanks, good to know. > So if disabling ports in hibernate doesn't work then we could turn off port power for > hosts with PPC==0. It should at least solve the issue for this particular system, > and not change current VBus policy in hibernate. Did a new version of this ever make it out? -Evan
