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<div class="section">
+ <h1 id="ram_s3_microcode">RAM, S3 and microcode updates</h1>
+
+ <p>
+ Not all memory modules work. Most of the default ones do, but you have to be careful
+ when upgrading to 8GiB; some modules work, some don't.
+ </p>
+
+ <p>
+ pehjota started collecting some steppings for different CPUs on several X200 laptops.
+ You can get the CPUID by running: <br/>
+ $ <b>dmesg | sed -n 's/^.* microcode: CPU0 sig=0x\([^,]*\),.*$/\1/p'</b>
+ </p>
+
+ <p>
+ What pehjota wrote:
+ The laptops that have issues resuming from suspend, as well as a laptop that (as I mentioned earlier in #libreboot) won't boot with any Samsung DIMMs, all have CPUID 0x10676 (stepping M0).
+ </p>
+
+ <p>
+ What pehjota wrote:
+ Laptops with CPUID 0x167A (stepping R0) resume properly every time and work with Samsung DIMMs. I'll
+ need to do more testing on more units to better confirm these trends, but it looks like the M0 microcode
+ is very buggy. That would also explain why I didn't have issues with Samsung DIMMs with the Lenovo BIOS
+ (which would have microcode updates). I wonder if VT-x works on R0.
+ </p>
+
+ <p>
+ What pehjota wrote:
+ As I said, 10676 is M0 and 1067A is R0; those are the two CPUIDs and steppings for Intel Core 2 Duo P8xxx CPUs with factory microcode. (1067 is the family and model, and 6 or A is the stepping ID.)
+ </p>
+
+ <p>
+ <b>
+ TODO: check the CPUIDs and test S3 resume and/or KVM on any C2D systems (including non-P8xxx ones, which I don't have here) you have available. I'd be curious if you could confirm these results.
+ </b>
+ It might not be coreboot that's buggy with raminit/S3; it might just be down to the microcode updates.
+ </p>
+
+ </div>
+
+ <div class="section">
+
<h2 id="unsorted">Unsorted notes</h2>
<pre>