Can't Mount CF-Card on boot of 2.6.15 Kernel on EPIA - VFS: Cannot open root device

[Markus Biermaier <mbier@office-m.at>]

Hi,

I use an EPIA MII6000E motherboard with CF-Card as hard-drive.
Since this device can't boot from CF-Card I boot from network via  
PXELINUX.
Works fine for kernel 2.4.25.

Now I want to change to kernel 2.6.15.4.

I boot an initrd, execute "linuxrc" and at this point I can mount the  
CF-Card as "hde1", inspect the file-system, ...

As soon as I finish "linuxrc" the root-fs should be mounted but the  
kernel panics with:

  VFS: Cannot open root device "hde1" or unknown-block(0,0)
  Please append a correct "root=" boot option
  Kernel panic - not syncinc: VFS: Unable to mount root fs on  
unknown-block(0,0)

"/tftpboot/pxelinux.cfg/Cxxxxxx":
------------------------- [ BEGIN Cxxxxxx ] -------------------------
DEFAULT standard
LABEL standard
KERNEL vmlinuz
APPEND initrd=initrd ramdisk_size=32768 root=/dev/hde1 acpi=off udev
------------------------- [ END   Cxxxxxx ] -------------------------

I tried:
------------------------- [ BEGIN linuxrc ] -------------------------
  ...
  mount /dev/hde1
  umount /proc
  umount /sys
  cd /mnt
  /mnt/sbin/pivot_root . initrd
  mount /sys /sys -t sysfs
  /sbin/udevstart
  /sbin/pcmcia-socket-startup
  mount /proc
  echo -n "42" > /sys/bus/pcmcia/devices/1.0/allow_func_id_match
  echo 0x3301 > /proc/sys/kernel/real-root-dev
  sleep 5
  exec <dev/console >dev/console 2>&1
  exec chroot . /bin/sh <<EOF
       umount initrd
       /sbin/blockdev --flushbufs /dev/ram0
       sleep 3
       exec /sbin/init 5
  EOF
------------------------- [ END   linuxrc ] -------------------------

I found that the root-fs is mounted twice. First as initial-RAM-Disk.  
Works ok.
Second as "real" root. With "printk" I found that in file "init/ 
do_mounts.c"
...
int err = do_mount_root(name, p, flags, root_mount_data);
...
The value of "name" is "/dev/root" before this statement.
After this "err" is -6 ("No such device or address").

BTW: When I have the line
  echo 0x3301 > /proc/sys/kernel/real-root-dev
in "linuxrc" the panic message
  "VFS: Unable to mount root fs on unknown-block(0,0)"
becomes
  "VFS: Unable to mount root fs on unknown-block(51,1)"

Any ideas?

Markus
 
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