On Thu, Sep 20, 2007 at 04:46:00PM +0100, Timothy Murphy wrote: > > I'm puzzled by the device /dev/eth0 , etc, It's just eth0, not /dev/eth0. > chosen by different drivers. It's not chosen by the drivers. It's automatically assigned by the kernel, in chronological order (regarding device registration). Also, the userland can change a device name as it pleases. (You could name it yourself: /sbin/ip link set eth0 name ne0 > This isn't a problem for me, just a mystery. > > For example, I just installed Fedora-7 on a laptop > (an old Sony PictureBook - C1VFK) > and when I attached it by ethernet to my LAN, > it immediately worked through /dev/eth0 , > despite the fact that /etc/modprobe.conf > had an incorrect "alias eth0 orinoco_cs", > while the driver in use is pcnet_cs . It's no longer necessary to define the module for a network device, as the boot scripts correctly load modules for the PCI devices they find. > > By contrast, on another laptop > although I have the correct "alias eth0 orinoco_cs" > in /etc/modprobe.conf , a strange device - > /dev/dev1375 , IIRC, was used. That's because a configuration already exists for eth0, that specifies a different MAC address from the one in the current device. Check /etc/sysconfig/network-scripts/ifcfg-eth0. It should have a line like: HWADDR=00:01:11:22:23:33 The correct value can be found with: /sbin/ip addr show dev1375 scope link Or just /sbin/ifconfig and check the output. The unusual name, dev1375, is dynamically generated so that it doesn't conflict with another device. > > So my questions are: > > 1) How does the machine decide which driver to use; and The modules/drivers have a list of PCI ids that are used to match drivers/modules with devices. > 2) How does it decide which device to use? > > Has it got something to do with udev ? It depends on your distribution. I think in F7 udev does the module loading, and there is development for persistent network device names, but that isn't yet used (by default) in Fedora 7. -- lfr 0/0
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