I have 1GB of memory in my machine currently and to use full 1GB I need to enable high mem support in kernel. IMHO it's not so good idea to enable it for ~200MB of additional memory.

I do a little research about that and I wonder is my sollution correct or no.

In the default configuration the LOWMEM_SIZE is set to 0x30000000 and this gives us a limit of 768MB's. But what if we change it to 0x40000000 ? This will allow us to use full 1GB of memory without high mem enabled.

I am aware that this will result in lack of the virtual space and propably cause many problems, but this can be avoided by lowering the KERNEL_START from default 0xc0000000 to for example 0xa0000000 or even 0x90000000 (I belive there is illegal to lower it bellow 0x80000000)

I already test this idea and I am using the custom kernel with:

LOWMEM_SIZE 0x40000000
KERNEL_START 0x90000000

And it's works just fine, but I guess the default values are set like that by a reason.

Reply to my own post again Nice ...

Anyway a patches to enable full 1G support without high memory support are available on
my home page at www.tbs-software.com/morgoth

Please note this require yaboot hack too also available on the same page (Untested as I doesn't use yaboot)

Have fun and remember to use it at your ownrisk

Hi, morgoth!
I'd love to make use of your howto or your patches.
The problem is i only have 512 MB

cheers
frostwork

This post got me curious, as I also have 1GB of memory. So upon encountering the DRI problems mentioned elsewhere, I disabled high memory support from the newly compiled kernel (I had to reboot anyway, why not waste it).

There was no performance difference - at least one I could notice. Should there be?