Hi Alan, On Tue, Aug 26, 2014 at 11:38 PM, Alan Stern <st...@rowland.harvard.edu> wrote: > 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.
Thanks for your response, I'm sorry that I didn't describe the question clearly. Because the EHCI support is built-in with Ubuntu kernel. I tried to find a way to disable that. Unfortunately, I only found "nousb" can disable it. But it will disable all the USB subsystem. Don't know if there is any chance to disable EHCI only. > > Alan Stern > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
