finding which pci device works as ide controller for root fs

[Arkadiusz Miskiewicz <arekm@pld-linux.org>]

Hi,

I need /dev/hdX -> pci id mapping for geninitrd script - with modular IDE I 
need to load some IDE controller driver from initrd to mount root fs.

Now I'm loading all modules for IDE devices found from:
awk ' { print $2 } ' /proc/bus/pci/devices
+ simple file which maps PCI ID to module name like
808684cb piix

How to find controller which is used for root fs (and do not load other 
modules)? I suppose that on 2.4 this is impossible from userspace but on 2.6 
maybe sysfs will be useful.

[arekm@mobarm arekm]$ ls -l /sys/block/hda/device
lrwxrwxrwx    1 root     root           46 2003-08-14 00:49 
/sys/block/hda/device -> ../../devices/pci0000:00/0000:00:11.1/ide0/0.0

Is it possible to get PCI ID from sysfs for specified device?

-- 
Arkadiusz Miśkiewicz    CS at FoE, Wroclaw University of Technology
arekm@sse.pl   AM2-6BONE, 1024/3DB19BBD, arekm(at)ircnet, PLD/Linux