Can't access ACPI memory through /dev/mem

From: Ph. Marek
Date: Fri Mar 12 2004 - 04:21:15 EST

Hello everybody!

My machine gives me for
$ cat /proc/iomem
00000000-0009fbff : System RAM
0009fc00-0009ffff : reserved
000a0000-000bffff : Video RAM area
000c0000-000c7fff : Video ROM
000d0000-000d9fff : Extension ROM
000f0000-000fffff : System ROM
00100000-0f7dffff : System RAM
00100000-0022ca51 : Kernel code
0022ca52-0029d8e3 : Kernel data
0f7e0000-0f7e7fff : ACPI Tables
0f7e8000-0f7fffff : ACPI Non-volatile Storage
80100000-801fffff : PCI Bus #01
80100000-8011ffff : Silicon Integrated Systems [SiS] SiS630 GUI
and so on.

Now I can access the whole area below the ACPI tables (I tried RAM, video and
system ROM, and kernel code/data).
But on reaching the ACPI tables and above (PCI space and so on) I get no data
(that is, vche blanks the screen).

I'd expect that for the PCI space - as this is really IO-memory and shouldn't
be messed with.

But I'd like to access the ACPI tables; especially the NVRAM, as some machines
store DMI data there.

This is on
Linux version 2.4.24-1-686 (herbert@gondolin) (gcc version 3.3.2 (Debian))
and an old 2.4.19 kernel.

Any tips? Help for accessing this memory space?


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