On Mon, Sep 30, 2024 at 07:23:29AM +0200, Olivier Dautricourt wrote: > If the controller reports HCSPARAMS1.maxports==0 then we can skip the > whole function: it would fail later after doing a bunch of unnecessary > stuff. It can occur on a buggy hardware (the value is driven by external > signals). What "buggy hardware" is this that can not pass the USB testing for this type of issue? > > Signed-off-by: Olivier Dautricourt <olivierdautricourt@xxxxxxxxx> > --- > drivers/usb/host/xhci-mem.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c > index d2900197a49e..e8406db78782 100644 > --- a/drivers/usb/host/xhci-mem.c > +++ b/drivers/usb/host/xhci-mem.c > @@ -2160,6 +2160,11 @@ static int xhci_setup_port_arrays(struct xhci_hcd *xhci, gfp_t flags) > struct device *dev = xhci_to_hcd(xhci)->self.sysdev; > > num_ports = HCS_MAX_PORTS(xhci->hcs_params1); > + if (num_ports == 0) { > + xhci_warn(xhci, "Host controller has no port enabled\n"); > + return -ENODEV; > + } Should this be backported to older kernels, if so, how far back if this is common hardware? thanks, greg k-h