On Tue, Jun 25, 2013 at 12:06 AM, Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx> wrote: > On Wed, Jun 19, 2013 at 11:52:10AM -0400, Alan Stern wrote: >> On Wed, 19 Jun 2013, Ming Lei wrote: >> >> > > There's a good chance this problem was caused by a change in the >> > > xhci-hcd driver. >> > >> > I am wondering why xhci-hcd may cause the problem since the affected >> > hub is 'Intel Corp. Integrated Rate Matching Hub' which is connected to >> > EHCI root hub. >> >> It's just a guess. You pointed out that the problem seems to be >> related to port routing, and the port routing code is part of the xHCI >> driver. >> >> The original bug report on Launchpad doesn't mention any earlier >> kernels working. Maybe the problem was caused by a change somewhere >> else, such as a change in the BIOS. > > It's entirely possible that the BIOS is not setting the xHCI port > routing mask properly, and the xHCI driver is not switching the ports > from EHCI to xHCI. My guess would be that the BIOS sets the USB 3.0 > port mask, but not the USB 2.0 port mask, which would cause the USB 3.0 > ports to be switched over, and not the USB 2.0 ports. So looks there is still the port routing thing between xhci hub and ehci rate matching hub? > It could also be that the BIOS is completely ignoring the writes to the > port registers as well. Can the reporters recompile with > CONFIG_USB_DEBUG and CONFIG_USB_XHCI_HCD_DEBUGGING turned on? That will > tell me which ports are being switched over. I will post your suggestion on Launchpad later. Thanks, -- Ming Lei -- 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
