Kernel only detection 2 GB of memory on AMD

[Vincent Stemen <vince.dragonfly@xxxxxxxxxxx>]

Hi.

Just wondering if there are there any known issues with detecting the
memory.  We have an AMD Opteron dual processor machine, and Dragonfly
only sees 2 GB with 4 GB in the machine.  This is Dragonfly
v2.5.1.901.g48d80-DEVELOPMENT.  We tried with both a regular default
kernel that installed from a snapshot ISO image and an SMP enabled
kernel that I compiled.

It also only sees 2GB on Dragonfly 2.4.1-release.

We tested with 4GB and 5GB of RAM.
The BIOS sees the full amount of memory.

The motherboard is a Iwill DK8S2-SATA with two single core AMD
Opteron(tm) processors.

dmesg shows

    DragonFly v2.5.1.901.g48d80-DEVELOPMENT #0: Thu Feb 25 00:16:40 CST 2010
        vince@quark.hightek.org:/usr/obj/u1/dragonfly/dfsrc/src/sys/GENERIC
    TSC clock: 2004881030 Hz, i8254 clock: 1193382 Hz
    CPU: AMD Opteron(tm) Processor 246 (2004.56-MHz 686-class CPU)
      Origin = "AuthenticAMD"  Id = 0xf5a  Stepping = 10
      Features=0x78bfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,MMX,FXSR,SSE,SSE2>
      AMD Features=0xe0500800<SYSCALL,NX,MMX+,LM,3DNow!+,3DNow!>
    real memory  = 2147418112 (2047 MB)
    avail memory = 2065563648 (1969 MB)
    ...
    DragonFly/MP: Multiprocessor motherboard
     cpu0 (BSP): apic id:  0, version: 0x00040010
     cpu1 (AP):  apic id:  1, version: 0x00040010
    ...

Top shows
     Memory: 6020K Active, 4384K Inact, 89M Wired, 44M Buf, 1898M Free

sysctl also shows 2GB.

--
Regards,
Vince