Use 2G RAM in 8548, vmalloc fail, adjust_total_lowmem

Dale Farnsworth dale at
Thu Jan 10 03:06:27 EST 2008

> I am using a MCP8548 board with kernel.
> And I would like to upgrade memory from 512MB to 2048MB.
> Finally, I realize this is not so easy as I think. I encounter several
> problems. :~~
> First, I change mem=512M to mem=2048M.
> 1. vmalloc fail problem
> So, I change kernel config in "advanced setup"
> Change  "Set maximum low memory" from 0x30000000 to 0x80000000.
> Change "Virtual address of kernel base" from 0xC0000000 to 0x60000000.
> Change "Set custom user task size" from 0x80000000 to 0x60000000

Just enable CONFIG_HIGHMEM=y to use your 2GB.  It's not worth the effort
to try making it all accessible as lowmem.


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