Linux – How to disable a usb sound device with udev

audiolinuxudev

How can I disable USB device by Vendor ID? So I have:

[root@piotr ~]# lsusb
Bus 001 Device 002: ID 058f:9254 Alcor Micro Corp. Hub
Bus 001 Device 003: ID 0d8c:000c C-Media Electronics, Inc. Audio Adapter
Bus 001 Device 004: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
Bus 002 Device 004: ID 05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB
Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 006: ID 0bc2:3320 Seagate RSS LLC SRD00F2 [Expansion Desktop Drive]

I want to disable

Bus 001 Device 003: ID 0d8c:000c C-Media Electronics, Inc. Audio Adapter

I need this unit in Windows environment but it disturb me Skype input (and only Skype). As temporary solution I just included snd_usb_audio in modprobe blacklist. But it is only workaround.
Or, (maybe better) is it possible to exclude this particular USB device from udev rules? But in /usr/lib/udev/rules.d there is not definition for this device. I mean about VendorID.

So my questions are:
Why it is working at all and can be seen by ALSA?
How can I exclude such VendorID and ProductID fron udev rules?
Any idea wanted

Best Answer

Add this line:

ACTION=="add", ATTR{idVendor}=="0d8c", ATTR{idProduct}=="000c", RUN+="/bin/sh -c 'echo 1 >/sys/\$devpath/authorized'"

to a new file (ex: my.rules) in /etc/udev/rules.d/

Fist Rule

ACTION=="add", DEV=="/devices/platform/pxa27x-ohci/usb1/1-2/1-2.2/1-2.2:1.0", SYMLINK+="huawey0"

Second Rule

ACTION=="add", KERNEL=="1-2.2:1.0", SYMLINK+="huawey0"

Third Rule

ACTION=="add", DEV=="/devices/platform/pxa27x-ohci/usb1/1-2/1-2.2/1-2.2:1.[0-4]", ATTR{bInterfaceNumber}=="00", SYMLINK+="huawey0"

Fourth Rule

ACTION=="add", ATTR{bInterfaceNumber}=="00", SYMLINK+="huawey0"

All these rules should do what you want now (I would use the first one personally).

Udev rule to match any usb storage device

A storage device is in the block subsystem, so you'll want SUBSYSTEM=="block" in your rule, like this:

ACTION=="add", KERNEL=="sd?", SUBSYSTEM=="block", ENV{ID_BUS}=="usb", \
    RUN+="/path/to/script"

If you're using systemd, you could run a systemd unit each time a USB storage device is added. Create the unit file, e.g. /etc/systemd/system/my-usb-rule.service:

[Service]
Type=oneshot
ExecStart=/path/to/script

and the rule, e.g. /etc/udev/rules.d/85-my-usb-rule.rules:

ACTION=="add", KERNEL=="sd?", SUBSYSTEM=="block", ENV{ID_BUS}=="usb", \
    ENV{SYSTEMD_WANTS}="my-usb-rule.service"

Now udev will trigger my-usb-rule.service (which in turn will execute your script) on any usb storage device add event.

Don't forget to reload the configuration after you edit the rules/units:

udevadm control --reload
systemctl daemon-reload

Best Answer

Related Solutions

Udev Rule to Match Multiple Node USB Device – Guide

Fist Rule

Second Rule

Third Rule

Fourth Rule

Udev rule to match any usb storage device

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