Handle the TSC sometimes stopping on older Intel CPUs with C2 by disabling both C2 and C3 if the TSC is used as the timecounter on these CPUs.
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Authored by jhb on Jan 5 2015, 6:02 PM.

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Reviewers

jkim
jhb

Summary

PR: 192316

Test Plan

Bug submitter tested this on a laptop that reported C3 as C2 (it
seems) when power management settings were changed in the BIOS.
This does disable C2 on some systems where it would be safe, but
all newer systems have a C-state invariant TSC which are not
affected by this change.

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rS FreeBSD src repository - subversion

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jhb updated this revision to Diff 3003.Jan 5 2015, 6:02 PM

jhb retitled this revision from to Handle the TSC sometimes stopping on older Intel CPUs with C2 by disabling both C2 and C3 if the TSC is used as the timecounter on these CPUs..

jhb edited the test plan for this revision. (Show Details)

jhb added a reviewer: jkim.

jhb updated this object.

jhb accepted this revision.Jan 29 2015, 4:47 PM

jhb added a reviewer: jhb.

This revision is now accepted and ready to land.Jan 29 2015, 4:47 PM

jhb closed this revision.Jan 29 2015, 4:47 PM