Re: 4GB of memory and NForce4SLI

Thomas Backlund wrote:

> Giuseppe Ghib=F2 wrote:
>=20
>> 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 addressing
>> space for PCI, etc., but for instance other mobos shows more than 3.3G=
B.
>> E.g. on Tyan 2885 I see 4096MB in BIOS and 3559132 with 'free'.
>>
>=20
> Atleast MSI nforce4 boards does only support ~3.5GB memory without the=20
> "memory hole" enabled...
>=20
>> The K8N Diamond has an option in BIOS to "Enable Hardware Memory Hole"=
,
>> 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 option =
to=20
>> kernel
>>
>=20
> you need to tell it how much memory you have using the "mem=3D" boot=20
> option...
>=20
> check this:
> http://hardware.mcse.ms/archive20-2005-8-216970.html
>=20
> at the end one user states:
>=20
> <quote>
>=20
>> Found the solution. Set the BIOS to Fill Memory Hole and then told Lin=
ux
>> it had 5G, i.e. mem=3D5G on the boot line.
>>
>> BTW a mem=3D line is required if when you set the BIOS to Fill Memory =
Hole,
>> without it you'll get a kernel panic when you boot. The FC3 installer=20
>> just
>> does a straight boot so it will panic on a machine with the Fill Memor=
y
>> Hole option set in the BIOS.
>=20
> </quote>
>=20
>=20
>> I tried also with kernel-2.6.14.2mdksmp-x86_64 but same results. Even
>> 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 than
>> currently supported.
>>
>> Bugs in kernel IOMMU?
>>
>=20
> you can also try booting with iommu=3Dforce
>=20
>=20
>> Bye
>> Giuseppe.
>>
>=20

In case someone might be interested, today was out the BIOS 1.10 for the =
MSI K8N=20
Diamond Plus. This seems have improved the handling of the 4G memory-hole=
, Here=20
is results:

- with kernel 2.6.12.18mdksmp =3D> "hardware memory hole" enabled in BIOS=
 =3D>
works and 'free' shows full 4GB (indeed 3.85GB which sound the highest va=
lue=20
obtained right now) of memory:

             total       used       free     shared    buffers     cached
Mem:       4042208     131780    3910428          0       2852      69948
-/+ buffers/cache:      58980    3983228
Swap:      6385796          0    6385796

while with "hardware memory hole" disabled it was before:

             total       used       free     shared    buffers     cached
Mem:       3348972     389712    2959260          0       6892     212548
-/+ buffers/cache:     170272    3178700
Swap:      6385796          0    6385796

What is also pretty strange is that USB port are working only when
hardware memory hole is enabled, otherwise USB (either with Legacy
USB enabled or disabled) remains still not-working
properly (indeed works with kernel 2.6.14-2mdk, but 2.6.14-2mdk doesn't
work with hardware memory hole enabled) with errors (as soon
as for instance an USB pen is plugged):

kernel: usb 2-9: new high speed USB device using ehci_hcd and address 10
kernel: usb 2-9: device descriptor read/all, error -110
kernel: usb 2-9: new high speed USB device using ehci_hcd and address 11
kernel: usb 2-9: device descriptor read/all, error -110
kernel: usb 2-9: new high speed USB device using ehci_hcd and address 12
kernel: usb 2-9: unable to read config index 0 descriptor/start
kernel: usb 2-9: can't read configurations, error -110
kernel: usb 2-9: new high speed USB device using ehci_hcd and address 13
kernel: usb 2-9: unable to read config index 0 descriptor/start
kernel: usb 2-9: can't read configurations, error -110

- with kernel 2.6.14-2mdksmp + hardware hole enabled in BIOS =3D> boot bu=
t soon=20
after a while (i.e. at end of inits) crashes with error:

   kernel panic - not syncing: PCI-DMA: high address but no IOMMU

  note that in this case I've also tried to boot using iommu=3Dforce and=20
iommu=3Doff, but same error.

- with 2.6.16.11-server-smp-3mdk, works for hardware memory hole enabled =
(sees
3.85GB too), but doesn't work with USB (errors in /var/log/messages are
similar to the ones above).

- with kernel 2.6.12-20.uc4mdksmp, same as 2.6.12.28mdksmp.

Bye
Giuseppe.