Re: [PATCH] usb: chipidea: host: Disable port power only if previously enabled

From: Alan Stern
Date: Sun Dec 29 2019 - 11:41:02 EST


On Sun, 29 Dec 2019, Guenter Roeck wrote:

> On Sat, Dec 28, 2019 at 02:33:01PM -0500, Alan Stern wrote:
> >
> > Let's try a slightly different approach. What happens with this patch?
> >
> > Alan Stern
> >
> >
> > Index: usb-devel/drivers/usb/core/hub.c
> > ===================================================================
> > --- usb-devel.orig/drivers/usb/core/hub.c
> > +++ usb-devel/drivers/usb/core/hub.c
> > @@ -1065,6 +1065,7 @@ static void hub_activate(struct usb_hub
> > if (type == HUB_INIT) {
> > delay = hub_power_on_good_delay(hub);
> >
> > + hub->power_bits[0] = ~0UL; /* All ports on */
> > hub_power_on(hub, false);
> > INIT_DELAYED_WORK(&hub->init_work, hub_init_func2);
> > queue_delayed_work(system_power_efficient_wq,
> >
>
> That doesn't make a difference - the traceback is still seen with this patch
> applied.

Can you trace what's going on? Does this code pathway now end up
calling ehci_port_power() for each root-hub port, and from there down
into the chipidea driver? If not, can you find where it gets
sidetracked?

Alan Stern