Re: macbook only sees 1GB of a 2GB RAM module

On Sat, May 30, 2020 at 07:23:58PM +0200, Jan Stary wrote:
> This is current/amd64 on a macbook2,1 (dmesg below).
> It has two RAM slots, each holding a 2GB module:

if you like using older Apple HW then

https://everymac.com/

is a very good resource. searching Macbook2,1 reveals the HW issue.

this specific limitation
https://everymac.com/systems/apple/macbook_pro/faq/macbook-pro-core-2-duo-3-gb-memory-limitation-details.html

>
> spdmem0 at iic0 addr 0x50: 2GB DDR2 SDRAM non-parity PC2-6400CL6 SO-DIMM
> spdmem1 at iic0 addr 0x52: 2GB DDR2 SDRAM non-parity PC2-6400CL6 SO-DIMM
>
> But of one of the 2GB, only 1GB is seen:
>
> real mem = 3171909632 (3024MB)
>
> I have tried swapping the mdules, it only happens
> in one of the two slots. If I put a 1GB module in there,
> the available memory is the same (in the other slot,
> 2GB is 2GB and 1GB is 1GB).
>
> Why is this? Does it have anthing to do with
> the memory map conflicts I see in the dmesg?
>

~rgc