Re: EFI approach and patches

[Bastian Blank <waldi@debian.org>]

On Mon, Aug 13, 2012 at 01:10:31AM +0100, Steve McIntyre wrote:
> 1. Add a new subarch of "efi" for i386 and amd64 in
>    libdebian-installer, worked out (as usual for EFI) from whether
>    /sys/firmware/efi is accessible. This filters through readily to
>    archdetect, used all over the place elsewhere in d-i.

This needs efivars loaded AFAIK. I'm not yet familiar with the EFI part
of the Linux kernel.

> 2. Build efi-reader for amd64 as well as ia64. Not sure if this
>    provides anything important, but it doesn't hurt. :-)

This is needed for what?

> 3. Build elilo-installer for amd64 too, and mark it as installable for
>    i386/efi|amd64/efi.

Does elilo provide 32 and 64-bit efi binaries? All the current machines
need 64-bit binaries.

> 4. Mark grub-installer as not installable for i386/efi|amd64/efi

No.

> 5. Mark lilo-installer as not installable for i386/efi|amd64/efi

Okay.

> 6. Several tweaks to partman-auto:
>   * Switch from fat16 to fat32 in ia64 recipes

Why?

>   The first of these needs testing - is EFI on ia64 *definitely* ok
>   with fat32, or must it have fat16? I've also upped the size of the
>   EFI partition to 512MB, a more sensible minimum in case of multiple
>   OS installs. I cloned tha ia64 recipes, then the diff shows the
>   changes since. Not 100% sure of the best approach for partman-auto,
>   I'll admit here. Thoughts?

It works fine with FAT16, however grub needs the partition properly
alligned.

> 8. partman-partitioning: for amd64/efi and i386/efi, use gpt instead
>    of msdos

Nope. EFI works fine with msdos.

> +/* Are we on an EFI system? Check to see if /sys/firmware/efi
> + * exists */
> +static int is_efi(void)
> +{
> +       int ret = access("/sys/firmware/efi", R_OK);
> +    if (ret == 0)
> +               return 1;
> +    else
> +               return 0;
> +}

Whitespace damage.

Bastian