On Wed, Feb 23, 2022 at 05:13:03PM -0500, Alan Stern wrote: > On Wed, Feb 23, 2022 at 09:58:56PM +0100, Heiner Kallweit wrote: > > On 23.02.2022 15:17, Alan Stern wrote: > > > 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. I believe this had been attempted in the past, but it does not appear that patch was ever accepted: https://lore.kernel.org/linux-usb/1517221474-19627-1-git-send-email-tqnguyen@xxxxxxx/ Jack > > This works on my system. However a consequence is that xhci->shared_hcd > > is NULL. > > Why is that? xhci->shared_hcd doesn't get set in usb_add_hcd(), so > skipping that call shouldn't cause it to be NULL. > > Note: If you skip calling usb_add_hcd(), you will also have to skip the > corresponding call to usb_remove_hcd(). There may be a few more > subtleties involved as well; like I said before, I'm not an expert on > this driver. You should ask the xhci-hcd maintainer for advice. > > Alan Stern > > > There are a few places like the following in xhci.c where > > this may result in a NPE. Not knowing the USB subsystem in detail > > I can't say whether these places are in any relevant path. > > > > static int xhci_run_finished(struct xhci_hcd *xhci) > > { > > if (xhci_start(xhci)) { > > xhci_halt(xhci); > > return -ENODEV; > > } > > xhci->shared_hcd->state = HC_STATE_RUNNING; > > > > > > > > > Alan Stern > > > > > >> What I can do: submit my patches as RFC, then there's a better basis > > >> for a discussion. > > >> > > >>> Alan Stern > > >> > > >> Heiner > > > > Heiner
