On Mon, 6 Jan 2014, Felipe Balbi wrote: > On Mon, Jan 06, 2014 at 06:58:01PM +0000, Holger Freyther wrote: > > Holger Hans Peter Freyther <holger@...> writes: > > > > Happy New Year, > > > > > > > xhci_hcd does not work with the Canon Lide scanners and has issues > > > with the suspend/resume handling. My Acer Aspire S5 notebook only > > > exposes USB3.0 ports and the distribution kernels generally have > > > xhci_hcd enabled and I don't have any USB3.0 hardware either. > > > > I am using the laptop with the ports routed to the EHCI and I didn't > > have any suspend/resume issues and I could even do the book keeping > > of sysmocom on my laptop now. > > > > Could we please get to a situation were users that only have USB3.0 > > ports can either drop to EHCI mode by unloading the xhci_hcd module > > or preferable be able to blacklist the xhci_hcd so I could even use > > the stock Debian kernel? > > you can blacklist any module you want on /etc/modprobe.d/ on most > distros (debian included). Blacklisting that way doesn't work if the module is built-in. It also may not work if the module is loaded by an initramfs. Finally, blacklisting xhci-hcd won't solve the problem at hand, because the ports get switched from EHCI to xHCI during early PCI processing, before xhci-hcd is loaded. The only check is for whether CONFIG_USB_XHCI_HCD is enabled, which isn't affected by blacklisting. As far as I can see, the code that switches the ports back to EHCI gets run only when the computer is turned off (and then only for some types of machines). The best way to solve this problem would be a boot command-line option. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
