[LinuxBIOS] problem about dram init

[aaron lwe]

On Dec 21, 2007 1:40 PM, Corey Osgood <corey.osgood at gmail.com> wrote:
>
> And now you're where I am. For some reason there's a reserved memory
> range _somewhere_ at the tolm, of some unknown size. I've found that
> reserving an extra 1MB doesn't work, but 32MB does. I've found nothing
> in the documentation I have to explain this. BTW, have you had to make
> any code changes other than the MA Map, and board-specific fixes? I'm
> wondering how generic that code really is.
>
> -Corey
>

Corey, I think I've found the cause of this problem, it's agp aperture memory
that caused this memory unusable. When I set agp aperture memory
size to 128MB, I found I could only use the tolm - 128 * 1024 memory,
and you set agp aperture memory size to 32MB, so reserving 32MB
worked for you. The smallest size I can set for agp apertur memory size
is 4MB and after setting that, memtest now reports 508MB(512MB - 4MB)
is working fine ;-)
Only I don't know why agp aperture memory would interfere with physical memory.