On Wed, Feb 23, 2022 at 01:26:23PM +0100, Heiner Kallweit wrote:
> On 23.02.2022 03:10, Alan Stern wrote:
> > On Tue, Feb 22, 2022 at 10:13:09PM +0100, Heiner Kallweit wrote:
> >>
> >> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> >> index 83b5aff25..e3f40d1f4 100644
> >> --- a/drivers/usb/core/hub.c
> >> +++ b/drivers/usb/core/hub.c
> >> @@ -1423,9 +1423,8 @@ static int hub_configure(struct usb_hub *hub,
> >> ret = -ENODEV;
> >> goto fail;
> >> } else if (hub->descriptor->bNbrPorts == 0) {
> >> - message = "hub doesn't have any ports!";
> >> - ret = -ENODEV;
> >> - goto fail;
> >> + dev_info(hub_dev, "hub has no ports, exiting\n");
> >> + return -ENODEV;
> >> }
> >>
> >> /*
> >
> > How about instead changing xhci-hcd so that it doesn't try to register
> > a USB-3 root hub if the controller doesn't have any USB-3 ports? I
> > think that would make more sense.
> >
> Right, this would be better. I checked and it seems to be a little bit
> bigger endeavor. If I let register_root_hub() fail, then this removes
> the USB3 bus/host (shared hcd), but also the USB2 bus/host.
> It took an additional change to xhci_plat_probe() to make it work on my
> system. Not sure what the impact could be on systems not using
> xhci_plat_probe(). Users may face the same issue like me, and having
> a USB3 hub with no ports may remove also the USB2 bus/host.
Don't change register_root_hub(). Just change xhci_plat_probe(); make
it skip the second call to usb_add_hcd() if there are no USB-3 ports.
Alan Stern
> What I can do: submit my patches as RFC, then there's a better basis
> for a discussion.
>
> > Alan Stern
>
> Heiner
