Kernel panic... Unable to mount root fs

Christian Gardner christian_gardner at
Tue Jul 1 12:01:54 PDT 2008

> Almost certainly it's because the necessary driver is not compiled
> into the kernel. The Ubuntu .config and kernel will probably not work
> for you because the drivers are modules and you need to have an
> initramfs to load them before mounting root. I don't recall the exact
> settings, but I think you'll need the following:
> For libata (newer SATA/PATA drivers):
> CONFIG_[SP]ATA_$yourcontroller=y
> CONFIG_BLK_DEV_SD=y # this is SCSI disk support
> For IDE (older drivers):
> CONFIG_BLK_DEV_$yourcontroller=y
> You can compile both libata and IDE into your kernel, and only one
> will be used. I forget which one is default in 2.6.22, but I think
> SATA disks will use libata and PATA disks will use IDE. If libata is
> loaded, you'll get /dev/sd* disks, and /dev/hd* disks for IDE.
> --
> Dan

Hi Dan, sorry if this message isn't threaded properly... thanks for your advice, I'm trying it out now but I'm not quite there yet.

I decided to bung in everything you say for both types of controller, I don't suppose it can hurt. Most of them were already enabled in the vanilla config file. I enabled CONFIG_ATA which hadn't been. That just leaves the two lines you suggest, in which I have to replace $yourcontroller with something intelligent. What might that be?

In the vanilla config file a whole bunch of CONFIG_BLK_DEV_$controllernames are enabled, but another whole bunch aren't. Meanwhile there are no entries in the mold of CONFIG_SATA_$anything or CONFIG_PATA_$anything, not even comments saying that such an option is not set!

How do I find out what controller I should put? The other responder to my Q  said I should try the lspci command so I did, I think this is the relevant line of output:

00:1f.2 IDE interface: Intel Corporation 82801GBM/GHM (ICH7 Family) SATA IDE Controller (rev 02)

Does that mean anything? Finally what I'm building all this on is a laptop, specifically the Toshiba Satellite P100-429 model which I bought about 18 months ago. Here's the 'official' page on it. Can't see what I want there...

I don't want to compile the kernel yet until I have some idea about those two lines, I suspect it would be pointless without somehow specifying the controller.

Thanks for your help so far!

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