[SeaBIOS] CHS translation (BIOS incompatibility)

Nikolay Ivanets stenavin at gmail.com
Tue Jun 5 17:09:54 CEST 2018


> As far as I know, QEMU should be able to tell SeaBIOS the exact
> geometry to use (eg, via qemu -hdachs c,h,s[,t] option).  If you're
> not getting the expected behavior, be sure to include the seabios log
> file - see: https://www.seabios.org/Debugging
>

Here is geometry when I have with patched bios (Windows boot):
    drive 0x000f57f0: PCHS=16383/16/63 translation=lba
LCHS=1024/255/32 s=143305920

Here is geometry I have with original Seabios (boot fails):
    drive 0x000f0bd0: PCHS=16383/16/63 translation=lba
LCHS=1024/255/63 s=143305920

Qemu limits what we can specify in CHS to 16383, 16 and 63
respectively and I don't see any combinations which will perform
necessary translation from PCHS=16383/16/63 to LCHS=1024/255/32.

I have attached 4 logs:

serial-no-chs.log - launch Qemu with original Seabios. No manual CHS
modifications.
serial-1024-16-32.log - launch Qemu with original Seabios. Manual
CHS(1024, 16, 32).
serial-8192-16-32.log - launch Qemu with original Seabios. Manual
CHS(8192, 16, 32).
serial-patched-bios.log - launch Qemu with PATCHED Seabios. No manual
CHS modification.


--
    +380979184774
    Mykola Ivanets
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