[syslinux] [PATCH] : Adding dlabel option to chain.c32

[Ady Ady]

> 
> As opposed to "label",
> "dlabel" ...
> https://github.com/ErwanAliasr1/syslinux/commit/ebf8cbf
> 
> SeaBIOS / GRUB2
> 
>     ...
>       ...
>       <target dev='vdc' bus='virtio'/>
>       <boot order='3'/>
>       ...
>       ...
>       <target dev='vdd' bus='virtio'/>
>       <boot order='4'/>
>       ...
>     ...
> 
> 
> # gdisk -l /dev/vdc
> ...
> Partition table scan:
>   MBR: protective
>   BSD: not present
>   APM: not present
>   GPT: present
> 
> Found valid GPT with protective MBR; using GPT.
> Disk /dev/vdc: ...
> ...
> Number  Start (sector)    End (sector)  Size       Code  Name
>    1            2048            6143   2.0 MiB     EF02  BIOS_Boot
>    2          411648         1435647   500.0 MiB   8300  GPT_Boot
>    3         1435648        22646783   10.1 GiB    8300  GPT_Root
>    4        22646784        25163775   1.2 GiB     8200  GPT_Swap
> 
> 
> 
> # gdisk -l /dev/vdd
> ...
> Partition table scan:
>   MBR: protective
>   BSD: not present
>   APM: not present
>   GPT: present
> 
> Found valid GPT with protective MBR; using GPT.
> Disk /dev/vdd: ...
> ...
> Number  Start (sector)    End (sector)  Size       Code  Name
>    1            2048            6143   2.0 MiB     EF02  BIOS_Boot_2
>    2          411648         1435647   500.0 MiB   8300  GPT_Boot_2
>    3         1435648        22646783   10.1 GiB    8300  GPT_Root_2
>    4        22646784        25163775   1.2 GiB     8200  GPT_Swap_2
> 
> 
> 
> /boot/extlinux/extlinux.conf 
> ...
> label localboot
>   com32 chain.c32
>   append dlabel=GPT_Root
> 
> label localboot 2
>   com32 chain.c32
>   append dlabel=GPT_Root_2
> ...
> 
> OR
> boot: chain dlabel=GPT_Root
> OR
> boot: chain dlabel=GPT_Root_2
> OR
> boot: chain dlabel=VanillaStrawberry
> OR
> boot: chain dlabel=literallywhateverentered
> 
> 
> The result is always the same,
> selected for boot is always drive with a higher boot priority,
> in this case - vdc
> 
> 

A couple of comments about this test that might be relevant.

First, LABEL directives (nothing to do with any "label" related to 
chain.c32) should not include spaces (e.g. "localboot 2" should not be 
used for a LABEL directive).

Now, regarding your 2 entries (i.e. LABELs) in extlinux.conf, what else 
is there? Would you please try using 'dlabel=GPT_Root_2' as your fist 
(LABEL) entry and as the DEFAULT label command?

The reason I am requesting this is because Fedora (which you usually 
use for your tests, IIRC) 24 was released without a patch in Syslinux 
for gcc5+ (which solves this strange behavior in the Syslinux boot 
prompt). Although Rawhide already includes the relevant patch for 
Syslinux's CLI, it is still not updated to the very latest / current 
Syslinux git master head (only updated to 6.04-pre1).

I guess the important question would be whether this test was performed 
from the current upstream Syslinux git master head + Erwan's patch, or 
rather from some older snapshot / build / version (+ Erwan's patch). If 
the former, then the problem in CLI seems to be back (in which case, 
the version of gcc being used to build these binaries might be a 
relevant detail).

Regards,
Ady.