Re: Mismatch between grub2 memmap and syslinux memmap while using memdisk

[KESHAV P.R.]

2010/12/22 Vladimir 'φ-coder/phcoder' Serbinenko <address@hidden>:
> On 12/22/2010 08:49 AM, KESHAV P.R. wrote:
>> Hi,
>>      I am trying to boot a floppy image in my Dell Laptop using
>> memdisk from syslinux . When memdisk is loaded from grub2 (linux16 and
>> initrd16), nearly 2 GB of ram is not usable out of 4 GB RAM. This is
>> the floppy image used
>> https://github.com/skodabenz/Tianocore_DUET_memdisk_compiled/blob/master/Tiano_EDK2_DUET_X64.img
>> and this is the grub2 config file
>>
>> menuentry "Boot DUET " {
>> linux16 ${prefix}/memdisk floppy ro nopass
>> initrd16 ${prefix}/Tiano_EDK2_DUET_X64.img
>> }
>>
>> I have attached the memmap outputs (from EFI shell) while loading the
>> image directly (memmap_direct.txt), memdisk through syslinux
>> (memmap_syslinux.txt), memdisk through grub2 (memmap_grub2.txt).
>> Loading memdisk through syslinux, ram space covered for the memdisk
>> and floppy image is only about 8 MB. Is this due to the way grub
>> allocates memory for initrd? Where is the bug? Memdisk or Grub2. I
>> think since memdisk works perfectly with syslinux, this has something
>> to do with grub2. Regards
>>
>>
> GRUB2 never loads the initrd above 0x37FFFFFF (compatibility reasons)
> and it's perfectly fine with all known linux versions. Apparently in
> this context syslinux loaded the initrd much higher. So the problem is
> on memdisk side.

But why nearly 2 GB of RAM is not usable when loading memdisk from
grub2 but no such problem occurs when memdisk is loded from syslinux?
Nearly 2 GB of RAM is marked as reserved when grub2 loads memdisk and
the floppy image (in memmap_grub2.txt file). That is really weird.


Keshav

>>
>>
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>
>
> --
> Regards
> Vladimir 'φ-coder/phcoder' Serbinenko
>
>
>
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