[plug] Debian Etch, kernel 2.6 and device special files
Peter F Bradshaw
pfb at exadios.com
Mon Jun 25 20:59:59 WST 2007
On Mon, 25 Jun 2007, Patrick Coleman wrote:
> On 6/25/07, Peter F Bradshaw <pfb at exadios.com> wrote:
> > What is udev. Is it something to do with USB? If so, I should have
> > pointed out that my sound cards are PCI devices.
> udev is the linux dynamic device creation thingo. Basically the
> concept is that when you plug a device in, or when a pci device is
> detected at bootup, the device's module uses udev to create the
> appropriate files. Evidently this isn't happening in your case, for
> whatever reason.
> > I have seen that stuff under /dev/.static/dev. However, from the name
> > (.static) and the ownership and permision of /dev/.static (drwx------,
> > root, root) I am assuming that these device files are not meant to be
> > used by user programs.
> They're not; my understanding is that the init scripts will copy the
> devices from /dev/.static to /dev every time the system boots.
> Basically, run your mknod commands in here and the devices created
> should a) appear in /dev next time you reboot and b) persist across
Thanks for the info. I'll have a scan through the init system to see
what I can see.
I do notice that in /etc/udev/udev.rules contains rules for ALSA devices
but non for OSS (which I am using).
The output from udevinfo on the dsp special file I have made is:
udevinfo --name /dev/dsp --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/sound/dsp':
looking at parent device '/devices/pci0000:00/0000:00:07.5':
DRIVERS=="VIA 82xx Audio"
looking at parent device '/devices/pci0000:00':
I cannot see anything wrong here but I do not know what to reasonably
Peter F Bradshaw: http://www.exadios.com (public keys avaliable there).
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