3.5GB memory limit? (fwd)
Eric W Biederman
ebiederman at lnxi.com
Thu Sep 26 06:37:00 CEST 2002
Kimon Berlin <kimon at hp.com> writes:
> At 12:12 PM Tuesday 2002-09-24, Bob Drzyzgula wrote:
> >Not that the 3.5GB thing is a surprise, but what chipset
> >were they talking about?
> You'll run into something similar regardless of the chipset. 32-bit PCI cards
> need MMIO below 4GB, so a chipset must provide a memory hole for them.
> A "nice" chipset will allow you to remap the affected memory above 4GB, and a
> "nice" operating system will allow you to use that remapped memory.
You can usually do a little better than 3.5GB if you only have a few
pci cards or pci cards with a small mmio hole.
With a single quadrics card plugged into the E7500 I can still keep
my hole down to 3.5GB. As far as I know the E7500 is either the only,
or at the very least one of the very first chipsets to offer a remapping
As far as accessing remapped memory. That is really dealing with memory
More information about the coreboot