DOS ain't dead

Wrong memory map using E820h? (Developers)

posted by Laaca , Czech republic, 06.01.2021, 23:30

I tested my pascal code for memory size detection. It is quite standard routine using E820h with fallback to E801h.
In every computer I tried it works nice and always via primary solution, via E820h.
(only on my P4 it reports not 512MB but 511MB).
But OK.
However on my now notebook Lenovo legion Y540 with 16GB RAM it detects only 2GB of RAM and the rest does not appear in the memory map.
I found no mistake in my code but was is even more important, all software information tools which rely on the E820h also report the 2GB of RAM.
See the screenshot from Astra:
http://www.laaca.borec.cz/imag0239.jpg

Sure - I can use for the memory detecion the SMBIOS scan with memory chips info but why the usual E820h does not work on my machine?
Is it a known bug on some BIOSes?
Or should I do some black magic voodoo with MSR registers?

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DOS-u-akbar!

Complete thread:

• Wrong memory map using E820h? - Laaca, 06.01.2021, 23:30 (Developers)
  • Wrong memory map using E820h? - Laaca, 07.01.2021, 10:43
    • Conflict between JEMMEX and BIOS service E820h - Laaca, 07.01.2021, 22:18
      • Conflict between JEMMEX and BIOS service E820h - Japheth, 08.01.2021, 04:57
        • Conflict between JEMMEX and BIOS service E820h - Laaca, 08.01.2021, 13:37