Re: 2.2.16 SMP: mtrr errors

John Cavan
2000-12-12T21:38:53Z

Petr Vandrovec wrote:
> > kernel: mtrr: base(0xd4000000) is not aligned on a size(0x1800000) boundary
> > last message repeated 2 times
>
> For some strange reason X thinks that you have 24MB of memory on the G450.
> You can either create 32MB write-combining region at 0xd4000000, or
> teach X that your device occupies 32MB and not 24 (you should do it anyway,
> region size can be only power of two)...

Petr, the Matrox card splits the memory between the two video screens
when running in a multi-head configuration and "pretends" that it is two
distinct cards. Thus, a 32 mb card will register an mtrr for 24mb and
for 8mb seperately when in this mode.

At line 1190 in arch/i386/kernel/mtrr.c the switch on Intel falls
through hitting the error message for Centaur. I know the comment says
to fall through, but is this correct? I've inserted a break at the end
of the Intel switch before and have not had problems, but I left it out
in the latest couple of kernels because of all the mtrr work being done,
waiting to see if there was resolution.

John