On Tue, 26 Aug 2014, Gavin Guo wrote: > Hi, > > I found that in the Baytrail-m platform if the "USB3.0 Configuration > in Pre-OS" is set to Auto in the BIOS, the system will boot with > EHCI-enabled. And test reboot 200 times. It sometimes hang in the > shutdown process "ehci-pci 0000:00:1d.0: shutdown." I also found that > sometimes hang in the booting up process. But it still black screen, I > can't see clearly where it hang. > > After doing some experiments, I found the following symptoms: > 1) Set the "USB3.0 Configuration in Pre-OS" to enable, the 200 times > reboot test can pass. Under the condition, lspci can't see the EHCI > [8086:0f34] controller. > > 2) Build a new kernel without the EHCI driver can also pass the 200 > times reboot test. > > 3) Put "echo -n "0000:00:1d.0" > /sys/bus/pci/drivers/ehci-pci/unbind" > in the /etc/rc.local can avoid shutdown hang but sometimes it also > hang in the booting up process during the 200 times reboot test. > > 4) I also found some messages in dmesg which show "ehci-pci > 0000:00:1d.0: port 1 reset error -110." It sounds like the BIOS is buggy. > If there is any possibility to disable the EHCI controller in the > Baytrail platform because the XHCI covers all the ports connected to > EHCI controller. You can disable the EHCI controller by setting "USB3.0 Configuration in Pre-OS" to enable, as you discovered. > And IIRC, there is only one host controller within > EHCI and XHCI can be enabled in the Baytrail platform. I'm also trying > to find out the kernel parameters to disable the EHCI driver, but > currently there is no available one. It's not a kernel parameter. You can blacklist the ehci-pci and ehci-hcd modules in /etc/modprobe.d/local.conf. Or you can turn off CONFIG_USB_EHCI_HCD in your .config and build a kernel with no EHCI support at all. 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
