Re: output from udevadm
On Sun, Jul 11, 2010 at 5:23 PM, <email@example.com> wrote:
> The following short transcript is from adapting the udevadm
> invocation in http://wiki.debian.org/udev to investigate
> 1394 support in my Squeeze system. Two questions.
> * What exactly is meant by "device specified by the devpath" in
> the output? According to the udevadm man page, devpath is
> the value assigned to --path; but that parameter is not present
> in the command below. No devpath is specified.
> * What exactly is '/class/ieee1394_protocol/raw1394'?
> /class is not a directory in the filesystem and /dev/raw1394
> is the only 1394 device I've found.
> ======= transcript=======
> joule:/dev# udevadm info --name=/dev/raw1394 --attribute-walk
> Udevinfo starts with the device specified by the devpath and then
> walks up the chain of parent devices. It prints for every device
> found, all possible attributes in the udev rules key format.
> A rule to match, can be composed by the attributes of the device
> and the attributes from one single parent device.
> looking at device '/class/ieee1394_protocol/raw1394':
> joule:/dev# ls /class
> ls: cannot access /class: No such file or directory
>From a filesystem perspective, there is an assumed /sys "in front of" /class/...
devpath is the /class/... equivalent of /dev/...
You can get it with
udevadm info --query=path --name=/dev/...