2 - Raspberry PI Community Projects

ATTRS{rev}==" "
ATTRS{state}=="running"
[...]
ATTRS{max_sectors}=="240"
[...]
looking at parent device '/devices/pci0000:00/0000:00:10.3/usb1/1-2/1-2.2':
KERNELS=="9:0:0:0"
SUBSYSTEMS=="usb"
DRIVERS=="usb"
ATTRS{configuration}=="iCfg"
ATTRS{bNumInterfaces}==" 1"
ATTRS{bConfigurationValue}=="1"
ATTRS{bmAttributes}=="80"
ATTRS{bMaxPower}=="100mA"
ATTRS{urbnum}=="398"
ATTRS{idVendor}=="4146"
ATTRS{idProduct}=="4146"
ATTRS{bcdDevice}=="0100"
[...]
ATTRS{manufacturer}=="USB Disk"
ATTRS{product}=="USB Mass Storage Device"
ATTRS{serial}=="M004021000001"
[...]
To create a new rule, you can use tests on the device's variables, as well as those of one of the
parent devices. The above case allows us to create two rules like these:
KERNEL=="sd?", SUBSYSTEM=="block", ATTRS{serial}=="M004021000001", SYMLINK+="
➥ usb_key/disk"
KERNEL=="sd?[0-9]", SUBSYSTEM=="block", ATTRS{serial}=="M004021000001",
➥ SYMLINK+="usb_key/part%n"
Once these rules are set in a file, named for example /etc/udev/rules.d/010_local.rules,
you can simply remove and reconnect the USB key. You can then see that /dev/usb_key/disk
represents the disk associated with the USB key, and /dev/usb_key/part1 is its first partition.
GOING FURTHER
Debugging udev's
configuration
Like many daemons, udevd stores logs in /var/log/daemon.log. But it is not
very verbose by default, and it's usually not enough to understand what's happening.
The udevadm control --log-priority=info command increases the
verbosity level and solves this problem. udevadm control --log-priority=
err returns to the default verbosity level.
Chapter 9 — Unix Services
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