Re: [coreboot] GRUB2 is not displaying Hard disk (hd0) partition

[Nico Huber]

Hi Dhanasekar,

On 05.07.2017 16:23, Dhanasekar Jaganathan wrote:
> Hi All,
>
> In GRUB2 command prompt, I am not seeing hard disk partitions like *(hd0),
> (hd0,msdos1),* Instead I am seeing* (ahci4), (ahci4,msdos1).*

the (hd*) numbering refers to those disks the BIOS has enumerated and
provides drivers for. You'd see them like this when you use SeaBIOS and
let it load a GRUB built for i386-pc.
> Usually, GRUB2 will list all the drives that coreboot presents to it. I
> think coreboot presenting drives in "AHCI" (not in "hd) format. So that
> GRUB2 displaying drives in AHCI format.

With GRUB as payload (I suppose that's your case), there is no BIOS that
presents disks and coreboot doesn't do such thing. So GRUB does what an
OS would do, load an AHCI driver and probe the disks by itself.
> Correct me, If I am wrong.
>
> Is there any changes to do in menuconfig?
> Can you please help me to solve this issue?.
> Please provide your comments.

You can get used to the (ahci*) numbering, or in case you need to sup-
port both schemes with the same config file: My default `grub.cfg`
generated by grub-mkconfig works around these differences with the
`search` command (see `info grub search`). For instance, it can set the
`root` variable to a partition found by its filesystem's UUID, e.g.:

search --no-floppy --fs-uuid --set=root
ad4103fa-d940-47ca-8506-301d8071d467

Hope that helps,
Nico

GRUB2 is not displaying Hard disk (hd0) partition

[Dhanasekar Jaganathan]

Hi Nico,
> You can get used to the (ahci*) numbering, or in case you need to sup-
> port both schemes with the same config file: My default `grub.cfg`
> generated by grub-mkconfig works around these differences with the
> `search` command (see `info grub search`). For instance, it can set the
> `root` variable to a partition found by its filesystem's UUID, e.g.:
> search --no-floppy --fs-uuid --set=root
> ad4103fa-d940-47ca-8506-301d8071d467

Actually, I am installing ONIE through GRUB2.  As per your suggestion, I
have changed all* (hd0)* to* (ahci4)* in ONIE's grub.cfg. Still, GRUB2 is
not finding (automatically) grub.cfg.
By default, *"memdisk"* is set to root. But I expect *"ahci"* should be
default root.

How to change gurb's default root to "ahci"?.

Please provide your comments.

Thanks,
Dhanasekar

On Thu, Jul 6, 2017 at 2:45 AM, Nico Huber  wrote:
> Hi Dhanasekar,
>
> On 05.07.2017 16:23, Dhanasekar Jaganathan wrote:
> > Hi All,
> >
> > In GRUB2 command prompt, I am not seeing hard disk partitions like
>
> *(hd0),
> > (hd0,msdos1),* Instead I am seeing* (ahci4), (ahci4,msdos1).*
>
> the (hd*) numbering refers to those disks the BIOS has enumerated and
> provides drivers for. You'd see them like this when you use SeaBIOS and
> let it load a GRUB built for i386-pc.
> > Usually, GRUB2 will list all the drives that coreboot presents to it. I
> > think coreboot presenting drives in "AHCI" (not in "hd) format. So that
> > GRUB2 displaying drives in AHCI format.
>
> With GRUB as payload (I suppose that's your case), there is no BIOS that
> presents disks and coreboot doesn't do such thing. So GRUB does what an
> OS would do, load an AHCI driver and probe the disks by itself.
> > Correct me, If I am wrong.
> >
> > Is there any changes to do in menuconfig?
> > Can you please help me to solve this issue?.
> > Please provide your comments.
>
> You can get used to the (ahci*) numbering, or in case you need to sup-
> port both schemes with the same config file: My default `grub.cfg`
> generated by grub-mkconfig works around these differences with the
> `search` command (see `info grub search`). For instance, it can set the
> `root` variable to a partition found by its filesystem's UUID, e.g.:
> search --no-floppy --fs-uuid --set=root
>
> ad4103fa-d940-47ca-8506-301d8071d467
>
> Hope that helps,
> Nico