linux does not see my RAM

[Tamas K Papp <tpapp@Princeton.EDU>]

Hi,

I have recently upgraded the ram in my G4 AlBook (PowerBook5,4).  I
had two 256 Mb modules there, and replaced one of them by a 1 GB one.

OS X recognizes that, eg System Profile/Memory says

Memory Slot		Size	Type		Speed
SODIMM0/J25LOWER	256 MB	DDR SDRAM	PC2700U-25330
SODIMM0/J25UPPER	1 GB	DDR SDRAM	PC2700U-25330

but

% cat /proc/cpuinfo
processor       : 0
cpu             : 7447A, altivec supported
clock           : 666MHz
revision        : 1.1 (pvr 8003 0101)
bogomips        : 663.55
machine         : PowerBook5,4
motherboard     : PowerBook5,4 MacRISC3 Power Macintosh
detected as     : 287 (PowerBook G4 15")
pmac flags      : 0000001b
L2 cache        : 512K unified
memory          : 1024MB
pmac-generation : NewWorld
% cat /proc/meminfo
MemTotal:       773552 kB
MemFree:        174120 kB
Buffers:         52712 kB
Cached:         357844 kB
SwapCached:          0 kB
Active:         358896 kB
Inactive:       201956 kB
HighTotal:           0 kB
HighFree:            0 kB
LowTotal:       773552 kB
LowFree:        174120 kB
SwapTotal:      499992 kB
SwapFree:       499992 kB
Dirty:           49352 kB
Writeback:           0 kB
Mapped:         224580 kB
Slab:            30412 kB
CommitLimit:    886768 kB
Committed_AS:   311040 kB
PageTables:       2356 kB
VmallocTotal:   186260 kB
VmallocUsed:     25100 kB
VmallocChunk:   159968 kB

Shouldn't Memory and MemTotal be 1280MB and 1310720 Kb, respectively?

I tried swapping the modules, it doesn't make any difference.  I tried
kernels 2.6.12-rc2 and 2.6.13.4 (I compiled both myself).  I tried
adding append="mem=1280M" to yaboot.conf (and of course did ybin -v
after that), but didn't change anything.

dmesg's first line says:

Total memory = 768MB; using 2048kB for hash table (at c0400000)

Thanks,

Tamas