On 17.09.19 17:28, Denis 'GNUtoo' Carikli wrote:
On Tue, 17 Sep 2019 10:21:38 +0200
Raw card type: D
Is there more information on such "card type" somewhere?
JEDEC specifies these reference cards. Sometimes you can get their specification for free (need to register to their webpage, though), sometimes they want money, I fail to see a pattern in what they publish.
In theory, there's a good chance that we could fix the training for type D. Though, I can't tell if there are more issues lurking than the failing read training.
Is there a way to avoid buying such "card type"?
I fear, no. Unless you can find somebody who already has a specific DIMM model and can ask them for the SPD data.
There are even more obvious specs that break compatibility, but the vendors won't tell you. It's really weird. If you ask me, the whole DIMM industry is broken. Instead of documenting their DIMMs and what the boards require, they publish QVLs? It's nuts. Maybe they just fear that customers could realize that DIMMs of one vendor are replaceable with those of another (they are, if they don't violate the spec).
Now I wonder, if, or why if not, somebody started a public database of SPD data?
last time we encountered problems with type D DIMMs, we concluded that it's not supposed to work [1]. Can you confirm if your DIMMs are stable with the vendor BIOS?
I didn't try with the stock BIOS on a Thinkpad X200 yet, but I tried with the stock BIOS on a Thinkpad X200 Tablet and it didn't work.
We should probably issue a warning when type D is installed.
Is there also a way or place where to issue warnings to people before they buy and install such cards? Is doc.coreboot.org for users too?
Yes, you can just push changes (under Documentation/ in the coreboot source repo) for review. Maybe a central GM45 page and a link to that for each board? I can write down the limits of the memory controller / raminit code, but as mentioned above, it will be hard to match that to actual DIMMs.
Nico