Re: [Bisected] 3.7-rc1 can't resume (still present in 3.9)

H. Peter Anvin
2013-07-12T23:46:24Z

On 07/12/2013 04:36 PM, Christian Sünkenberg wrote:
>
> Jonas tried your patch and it fixes suspend/resume on his T43, although
> IMHO the safest approach would be to just add an exception for
> Vendor==Intel && Family==6 && Model==13, or more generally Vendor==Intel
> && !supports_long_mode, as the same erratum also warns about wrmsr
> possibly not triggering a GP either.
> Anyways, at least on this specific MSR with the Pentium M Jonas tested,
> it behaved correctly on every try, so I'd say your patch does the trick,
> thank you very much!
>

Using vendor matches is not really a great way to deal with things that
can better be handled analytically.

If WRMSR doesn't fault, it is not a problem...

> As a side note, I found a similar erratum #33 in "Pentium® Processor
> Specification Update" for Intel P54C (Family 5, Model 2), which would,
> supposed there are P54C systems with ACPI sleep/resume support, result
> in MSR 0 (P5_MC_ADDR) to be saved and restored instead of nonexistent EFER.

Doesn't really matter, as we'd only read that one after an #MC.

-hpa