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. 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. Sarah Sharp -- 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
