[vox-tech] Can't mount root while booting 2.6.5 kernel

[Chris Jenks]

  I wrote recently about a problem I was having getting PCMCIA working
under a custom 2.6.5 kernel. Actually, I meant the 2.6.3 kernel, because
when I tried upgrading to the 2.6.5 kernel source that recently appeared
in the Sarge source tree, the boot fails after about one page of messages.
The following lines appear under the working 2.6.3 kernel but not the
2.6.5 kernel:

Uniform Multi-Platform E-IDE driver Revision: 7.00alpha2
ide: Assuming 50MHz system bus speed for PIO modes; override with idebus=xx
hda: IBM-DTCA-23240, ATA DISK drive
ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
hda: max request size: 128 KiB
hda: 6354432 sectors (3253MB) w/486KiB cache,CHS=6304/16/63
  hda: hda1 hda2 hda3

and a few lines later, 2.6.3 gives:

VFS: Mounted root (ext2 filesystem) readonly.

but 2.6.5 gives:

VFS: Cannot open root device "303" or unknown-block(3,3)
Please append a correct "root=" boot option
Kernel panic: VFS: Unable to mount root fs on unknown-blobk(3,3)

  From googling I've found that this is a common problem under 2.6 kernels
but there seems to be a variety of causes. I've tried setting the kernel
command line to root=/dev/hda3, root=303 or devfs=monount. I've removed
LBA32 from lilo.conf, installed module-init-tools and udev, and I've
confirmed that ide.o is being compiled into the kernel. The reason I
installed udev was that the kernel config help for "/dev file system
support" says that devfs has been replaced by udev, but the 2.2.20 kernel
(my working fallback) doesn't (try to) start udev until after VFS. My
starting configuration for 2.6.5 was the one that produced a booting
kernel for 2.6.3.

  The hardware is an IBM Thinkpad 701C 486 with an ISA bus (no PCI) and an
ATA-3 hard drive (according to hdparm). CONFIG_ISA=Y in the kernel config.
If anyone has any suggestions, I would really appreciate them.

  Thanks,

    Chris