Addressing over 8G is not supported by the chipset used on nehalem thinkpad laptops (X201)
Stupid limitation, but it is not the CPU fault. On Sat, Jan 21, 2017 at 5:55 AM, Stefan Tauner < stefan.tau...@alumni.tuwien.ac.at> wrote: > Hi Vladimir, > > since you have REed the raminit for Nehalem I'd like you to ask if you > have any knowledge, information or pointers about using 8 GB DIMMs with > it or even using more than 8 GB in total. In my case it is about an > Arrandale i5-520M (in a Thinkpad 410s). > > I know that an i7-820QM (Clarksfield) is perfectly capable of working > with 8 GB DIMMs and probably up to 32 GB or even more (the Thinkpad > W510 has 4 DIMM slots and I have tested it with 20 GB) and that is from > around the same time as the Arrendale chips - which does not mean > anything but I still refuse to accept that Nehalem is that limited. The > official specs are not trustworthy IMHO and cpuid(1) and /proc/cpuinfo > show the same physical address width of 36 bits (which would indicate a > maximum of 64 GB). > > The current raminit for Nehalem in coreboot is not able to train the two > 8 GB DIMMs I have tested so far. I have added a debug output to > choose_reg178 in the first loop before the margins are compared to > STANDARD_MIN_MARGIN that shows that all margins are 0. If there is > anything I could try or information I can provide, please let me know. > > The (ancient) vendor firmware I've been using on the T410s does > sometimes manage to boot Linux with an 8 GB DIMM (dmesg is attached > including the e820 map), but it is quite broken and memtest86 locks up > or reboots within seconds so that's probably not a good target for RE > efforts. :) > > -- > Kind regards/Mit freundlichen Grüßen, Stefan Tauner > > -- > coreboot mailing list: coreboot@coreboot.org > https://www.coreboot.org/mailman/listinfo/coreboot >
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