# troubles with kernel

## az20110303

Hello everyone  :Smile:  . So i decided to migrate to gentoo from ubuntu. i did some efforts before, but they all were half successfull. 

i am installing gentoo on one physical drive with ubuntu. i compiled kernel 2.6.37-gentoo-r4 using configs from kernel-seeds.org. It seems i did not miss anything in config file, i checked it twice.

After kernel is compiled i 

```
sudo update-grub2
```

in ubuntu and gentoo entry appears in grub.cfg

here how it looks: 

```
menuentry "Gentoo Base System release 1.12.14 (on /dev/sda5)" --class gnu-linux --class gnu --class os {

   insmod part_gpt

   insmod ext2

   set root='(/dev/sda,gpt5)'

   search --no-floppy --fs-uuid --set=root 6cace587-a44a-4bc2-87a8-dd72a3fe82ed

   linux /boot/kernel-2.6.37-gentoo-r4 root=/dev/sda5

}
```

when trying to boot this entry i get error:

http://oi53.tinypic.com/s688c7.jpg

i also tried to use change kernel options in grub.cfg

```
   linux /boot/kernel-2.6.37-gentoo-r4 root=UUID=6cace587-a44a-4bc2-87a8-dd72a3fe82ed
```

but result was the same

i am not sure is it error in my manually compiled kernel or some incompatibility with ubuntu grub2.

any help will be appreciated.

----------

## Jaglover

Looks like missing root filesystem support in kernel.

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## az20110303

 *Jaglover wrote:*   

> Looks like missing root filesystem support in kernel.

 

i included support of ext2,3,4 reiserfs into kernel. file system of my gentoo partition is ext4. partition table of hard disk is GPT.

----------

## whiteghost

please post your .config and lspci -kvm on pastebin

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## az20110303

 *whiteghost wrote:*   

> please post your .config and lspci -kvm on pastebin

 

config http://pastebin.com/Gb25ArrZ

lspci http://pastebin.com/5F9d1sLz

----------

## whiteghost

from your config

```
 CONFIG_SATA_AHCI is not set
```

set this to yes, hope it helps

----------

## az20110303

 *whiteghost wrote:*   

> from your config
> 
> ```
>  CONFIG_SATA_AHCI is not set
> ```
> ...

 

Thanks for help, but still the same problem=(

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## Randy Andy

Hi az20110303.

as i see in your .config, you have to set this option and the belonging for your kind of system, which submenue appears only after setting this to yes:

```

# CONFIG_EFI is not set

```

you will see some help text for clarification your eventually upcoming questions.

AFAIK you ned this option, cause you're using a GPT partition scheme and GRUB2.

Much success,

Andy.

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## az20110303

 *Randy Andy wrote:*   

> 
> 
> ```
> 
> # CONFIG_EFI is not set
> ...

 

Thanks a lot, that helped! Though i did not set 

```

# CONFIG_EFI is not set

```

But i set

```

CONFIG_EFI_PARTITION=y

```

This one was enouht for kernel to boot  :Very Happy: 

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## az20110303

There's one more trouble with ext4 on new kernels. To mount r/w ext4 root file system kernel should be compiled with CONFIG_LBDAF. May be it will help to somebody  :Smile:  .

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## Hu

 *az20110303 wrote:*   

> There's one more trouble with ext4 on new kernels. To mount r/w ext4 root file system kernel should be compiled with CONFIG_LBDAF.

 This only applies to x86 kernels, not amd64 kernels.  Additionally, depending on other factors, an x86 kernel can mount an ext4 filesystem without having LBDAF=y.  I have an x86 system using ext4 for all its filesystems, and it works fine even though I did not set LBDAF.

----------

