Re: [Kernel] 4GB of memory and NForce4SLI

Luiz Fernando Capitulino wrote:

 > On Mon, 27 Mar 2006 18:59:39 +0200
 > Giuseppe Ghib=C3=B2 <[email protected]> wrote:
 >
 > | I tried currently 2006.0 with kernel 2.6.12.18mdksmp-x86_64 into
 > | a MSI K8N Diamond Plus motherboard with Athlon64-X2 4800. The
 > | motherboard has chipset Nforce4-sli and 4 modules of 1GB each.
 > |
 > | Currently the BIOS sees 3328MB of memory and in such way
 > | it correctly boots with 2.6.12.18mdksmp and free shows
 > | 3350260 kB free mem with the 'free' command.
 > | How to obtain the rest of 700MB of memory? OK, there is the addressi=
ng
 > | space for PCI, etc., but for instance other mobos shows more than 3.=
3GB.
 > | E.g. on Tyan 2885 I see 4096MB in BIOS and 3559132 with 'free'.
 >
 >  It's a BIOS issue then, isn't it? When we talked via IRC, I thought i=
t
 > was a kernel problem..

Why should be a BIOS issue? I have only two kind of setting: Memory
Hole Disabled and Memory Hole Enabled. Other BIOS parameters, like
"MTRR Mapping Mode" (which can be set to "Continuous" or "Discrete") have=
 no
effect. Maybe is a general waeakness of the kernel to get the 4096MB of m=
em on=20
NForce4? Note also that I cited Tyan only to show that with 4GB of ECC me=
mory=20
the PCI addressing space cause 4GB to shrink also on other kind of mother=
boards,=20
but the case of the MSI K8NDiamond Plus, IMHO the shrinkage is too much: =
at=20
least 200MB of fewer memory. I heard some people were able to get 3.6GB o=
f=20
memory also on much older motherboards such as based on VIA chipset like =
ASUS=20
A8V, which is much more than the MSI one.

 >
 > | The K8N Diamond has an option in BIOS to "Enable Hardware Memory Hol=
e",
 > | which enable memory remapping around the memory hole. The CPU needed
 > | for this option is at least stepping E0. A64-4800X2 is stepping E6
 > | so should be supported. Once the "Hardware Memory Hole" has been
 > | enabled the BIOS sees 4096MB of memory. But the kernel is no
 > | longer able to boot. Latest logs were:
 > |
 > | ...
 > | Freeing unused kernel memory: 196k freed
 > | Kernel panic - not syncing: No init found. Try passing init=3D optio=
n to kernel
 > |
 > | I tried also with kernel-2.6.14.2mdksmp-x86_64 but same results. Eve=
n
 > | with kernel-linus-2.6.16.15mdksmp-x86_64 gives the same (plus error
 > | during 3ware modules scsi probing:
 > |
 > | scsi: host 0 channel 0 id 0 lun 0x5a5a5a5a5a5a5a5ahas LUN larger tha=
n
 > | currently supported.
 >
 >  That sequence '0x5a5a5a5a' is the kernel's poisoning patter, I can't
 > say whether it's happening due a kernel issue.
 >
 >  Did you try to update your BIOS? And why do you need to change BIOS'
 > options? I mean, is it the _right_ way to do it?

It's not possible to upgrade the BIOS, because MSI doesn't have
released any firmware upgrade for this model of motherboard. In other
words default one is the latest.

 >
 > | Bugs in kernel IOMMU?
 >
 >  Better to try the simpler first.
 >