[Request] Dell Inspiron 17R SE (7720) BIOS: add 32GB RAM support

[DeathBringer]

i7-5775C's datasheet hasn't info about support of 8 Gb chips.
But i3/i5-i5-5xxxU's datasheet has a reference to 8 Gb chips! Read Table 5. Supported DDR3L/DDR3L-RS Memory Down Configurations Per Channel.
Note that i3/i5-i5-5xxxU support a maximum of one DIMM per channel - read 2.1 System Memory Interface.
So some CPU with Broadwell core has undocumented support of 8 Gb chips.
Updating MRC can increase the stability. But even without updating MRC CPU recognizes full capacity of memory, not just a half.

[sciff]

But it's documented, isn't it? However, it's only for the memory that is was soldered to the motherboard. Hence the words Memory Down in the table heading. And it's only for U processors which are dual-core, have low TDP and are supposed to be used in ultra-thin devices.
There's no mention of 8Gbit chips in Mobile 5th Generation Core Family Datasheet, although I'M say that their 16GB So-DIMM can be used with these processors.
This is clearly undocumented support. Which makes me think that Ivy Bridge could also, in principle, support 8Gbit chips. Am I wrong?
P.S. Like I said before, mobile 5th Gen Core i7 processors with four cores officially have 32GB memory limit, just like 3rd Gen i7, or Ivy Bridge.

[DeathBringer]

Which makes me think that Ivy Bridge could also, in principle, support 8Gbit chips.

I don't think so. They are too old CPU...

[sciff]

How to make sure that they don't?

[DeathBringer]

Only real experiment can help.
If only a half of memory is recognized on any laptop with Ivy Bridge CPU then 8 Gb chips aren't supported by this core.
If all such laptops can't boot then it's maybe MRC's problem.

[sciff]

All right! Thank you!

[bordoom]

All right! Thank you!

Please, tell me
did you manage to try 2x16gb memory on inspiron 7720?
successfully?

[segfault_bilibili]

All right! Thank you!

Please, tell me
did you manage to try 2x16gb memory on inspiron 7720?
successfully?

I would advice you to give up.

My results on Haswell are negative. I have actually tried on a IvyBridge laptop (Dell Inspiron E6430, which is supported by Coreboot) as well, negative as well.

I digged this down to the configuration registers (typo, fixed) of the integrated memory controller. It turns out that (on consumer-grade CPUs, and entry-level server E3 models) Intel does not allow fine-grained configuration on how many column address lines to be used - instead it only accepts size_mb as the configuration parameter.

That's saying, Intel literally limited the supported capacity per module to 8GB (another typo fixed, 16GB is not supported) at hardware level, yes just the overall capacity per module, not density, not column address line count (even if column address lines are multiplexed with row lines so that physically this should not be a problem).