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I've just reinstalled Debian on my Sony VAIO laptop, and my dmesg and virtual consoles all get spammed with the same messages over and over again.

[   59.662381] hub 1-1:1.0: unable to enumerate USB device on port 2
[   59.901732] usb 1-1.2: new high-speed USB device number 91 using ehci_hcd
[   59.917940] hub 1-1:1.0: unable to enumerate USB device on port 2
[   60.157256] usb 1-1.2: new high-speed USB device number 92 using ehci_hcd

I believe these messages are coming from an internally connected USB device, most likely the webcam (since that's the only thing that doesn't work). The only way I can seem to have it shut up (without killing my actually useful USB ports) is to disable one of the USB host controllers:

# echo "0000:00:1a.0" > /sys/bus/pci/drivers/ehci_hcd/unbind

This also takes down my Bluetooth interface, but I'm fine with that.

I would like this setting to persist, so that I can painlessly use my virtual console again in case I need it. I want my operating system (Debian amd64) to never wake it up, but I don't know how to do this. I've tried to blacklist the module alias for the PCI device, but it seems to be ignored:

$ cat /sys/bus/pci/devices/0000\:00\:1a.0/modalias 

$ cat /etc/modprobe.d/blacklist
blacklist pci:v00008086d00003B3Csv0000104Dsd00009071bc0Csc03i20

How do I ensure that this specific PCI device is never automatically activated, without disabling its driver altogether?

-edit- The module was renamed recently, now the following works from userland:

echo "0000:00:1a.0" > /sys/bus/pci/drivers/ehci-pci/unbind

Still, I'm looking for a way to stop the kernel from binding that device in the first place.

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Would an acceptable approach be to disable this particular USB device through the USB bus rather than the PCI bus? –  slm Feb 20 '13 at 14:06
Also are you sure you can blacklist using a pci:... string like that? I've only ever seen kernel modules blacklistable in the /etc/modprobe.d/blacklist file. Couldn't you use lspci -k to identify which module the device wants and then black list that instead? –  slm Feb 20 '13 at 14:13
After adding the entry to the blacklist, did you update-initramfs -u -k all? –  Stefan Seidel Feb 21 '13 at 10:14
@StefanSeidel: Good point. I have now, but it doesn't seem to help. Perhaps slm is right in thinking that blacklisting a modalias like this needs a different syntax or method. –  Rhymoid Feb 21 '13 at 14:55
@slm: I'm not sure if I can block modaliases through the modprobe blacklist (my system seems to ignore the line I gave it), but I can't just remove the module (ehci_hcd), since that would disable all USB hosts on my system. I just want to disable this specific device, based on its vendor, dev, subvendor, and subdev. –  Rhymoid Feb 21 '13 at 14:58
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6 Answers

None of the answers solved my similar problem, but they did put me on the path to solving it!

My syslog error:

[  334.940158] hub 1-0:1.0: unable to enumerate USB device on port 7

This is an internal usb hub-port for a bluetooth option I do not have.

unbind to the pci device just resulted in the hub popping back up as another hub (5 in my case) and flooding syslog further.

By chance I noticed an unbind structure under /sys/bus/usb/drivers/hub. Using examples above I just added the following in rc.local:

echo "1-0:1.0" > /sys/bus/usb/drivers/hub/unbind

Result is syslog silence! Now to add kshurig's script example for power management and I should be golden.

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Found this thread on askubuntu:

Using lspci -vv to identify a device's PCI slot that you want to disable, it sounded like you could use this command to turn that slot's device off:

% echo 0 > /sys/bus/pci/slot/$N/power
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I know how I can disable it at any other time, but I want to stop the kernel from activating it at all. Besides, since this is a hardwired PCI device (like most USB controllers), it has no slot. The machine I'm talking about is a laptop, and the only slot it has (/sys/bus/pci/slots/1) is the ExpressCard slot on the outside, which I can manually vacate. –  Rhymoid Feb 20 '13 at 8:39
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not an answer to your question as much as a work around.

Why not simply suppress the logging of the messages to the console by modifying syslog / (I don't know if you use syslog or rsyslog or something else, so I can't really point you more specifically in the correct directory, but if you search your syslog config files for "console" and "tty", that would give you a good starting place - in fact, you can probably change console to /dev/tty1 [for example] and have messages only log to tty1 rather then all consoles.

The other solution (to answer your question, but I don't like), you could blacklist the ehci_hcd module (if its loaded), or recompile your kernel to use it only a s a module. Have a look at http://www.cyberciti.biz/faq/rhel-redhat-centos-kernel-usb-reset-high-speed-ehci_hcd/ which resolves exactly the question you are asking

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If you don't want it to even be started you can't do that. The computer has to run a POST. Sorry dude but your out of luck.... you could just pull it out.

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When you already have echo "0000:00:1a.0" > /sys/bus/pci/drivers/ehci_hcd/unbind in /etc/rc.local for boot than you just need to put it into a script for the power management deamon aswell.

Goes like this: Create an executable bash script file named 0_disable_webcam in directory /etc/pm/sleep.d/:

case "$1" in
                echo "0000:00:1a.0" > /sys/bus/pci/drivers/ehci_hcd/unbind

It should work instantly. I tried it with an usb thumb drive and it worked (meaning it remained disabled) as long as the drive was plugged. Replugging would need udev rules but since your webcam will not be unplugged it should work. If that does not do the trick I have another suggestion.

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If the above does not work then you have to find the correct usb port. I guess it is "1-1.2" ( otherwise check with tree /sys/bus/pci/devices/0000\:00\:1a.0/ under "usbX" which means the port is a similar number). If it is "1-1.2" instead of your echo "0000:00:1a.0" > /sys/bus/pci/drivers/ehci_hcd/unbind the script should have echo "auto" > /sys/bus/usb/devices/1-1.2/power/control; echo -n "1-1.2" > /sys/bus/usb/drivers/usb/unbind. –  kschurig Feb 24 '13 at 0:01
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You can remove a PCI device by adding a udev rule under /etc/udev/rules.d :

ACTION=="add", KERNEL=="0000:00:03.0", SUBSYSTEM=="pci", RUN+="/bin/sh -c 'echo 1 > /sys/bus/pci/devices/0000:00:03.0/remove'"

Replace 0000:00:03.0 with the pci device address you want to remove

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This is pretty useful. However, as the OP mentioned, this will result in all USB ports going down. Is there anyway to add a rule for a specific device and vendor id so that the devices works with all other USB ports but will disregard a given device? –  Mosty Mostacho Jun 3 at 4:33
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