Read a section 9.3 this document:
http://mirror.atrpms.net/fedora/linux/releases/7/Fedora/i386/os/RELEASE-NOTES-en_US.html
On Mon, 2007-07-02 at 22:37 -0400, Srikanth Konjarla wrote:
Thanks for the response. Interestingly, i could not find any BIOS options pertaining to memory. I found the following. # cat /proc/mtrr reg00: base=0xfeda0000 (4077MB), size= 128KB: write-back, count=1 reg01: base=0xfff00000 (4095MB), size= 1MB: write-protect, count=1 reg02: base=0x00000000 ( 0MB), size=2048MB: write-back, count=1 reg03: base=0x80000000 (2048MB), size=1024MB: write-back, count=1 reg04: base=0xc0000000 (3072MB), size= 256MB: write-back, count=1 Could be incompatible memory modules or something? Thanks Srikanth Wolfgang S. Rupprecht wrote: > Srikanth Konjarla <srikanth.konjarla@xxxxxxxxx> writes: >> I am running F7 in 64-bit mode on a laptop. I have upgraded the memory >> from 3G to 4G (Bios confirms it) but kernel sees only 3.2G (i have >> passed mem=4096M kernel parameter). Wondering if i am missing anything >> here. > > What you are missing is the really nasty design of IBM-PC legacy > memory allocations. ;-) > > Play around in your BIOS and see if you can map the excess memory > above 4GB. Often the labels for the settings will have the term > "MTRR" in the name. When you get it right "cat /proc/mtrr" should > show the extra 750MBytes mapped above 4 Gigs. The setting names might > not make much sense (at least they don't on my Tyan). You might need > to just try them all and see what effect they have on the linux mttr > settings. Here is what it looks like on my board when I have it set > to see all 4 GBytes: > > $ cat /proc/mtrr > reg00: base=0x00000000 ( 0MB), size=2048MB: write-back, count=1 > reg01: base=0x80000000 (2048MB), size=1024MB: write-back, count=1 > reg02: base=0xc0000000 (3072MB), size= 256MB: write-back, count=1 > reg03: base=0xcff00000 (3327MB), size= 1MB: uncachable, count=1 > reg04: base=0x100000000 (4096MB), size= 512MB: write-back, count=1 > reg05: base=0x120000000 (4608MB), size= 256MB: write-back, count=1 > reg06: base=0xd8000000 (3456MB), size= 128MB: write-combining, count=2 > > Notice the first 3 entries are 3.25 GBytes (reg00, reg01 and reg02). > The last 0.75GBytes are mapped above 4GByte (reg04 and reg05). > > -wolfgang
