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SubjectRe: [Patch] tsc-disable_A5
On Sat, 15 Jun 2002, Mikael Pettersson wrote:

> I disagree with Alan's recommendation.

So do I.

> The real problem is that the kernel confuses a CPU-level property
> (do the CPUs have TSCs?) with a system-level property (are the
> TSCs present and in sync?). CONFIG_X86_TSC really describes the
> latter property, for the former we have the cpu_has_tsc() macro.

Well, CONFIG_X86_TSC simply asserts we have TSCs present and in sync and
cpu_has_tsc is a run-time check for the same. The X86_FEATURE_TSC bit
shouldn't be set (and e.g. "notsc" takes care of this) unless TSCs work
correctly as it's both used internally and exported to the userland. For
low-level fiddling with TSCs one can use cpuid either directly or with the
cpuid driver.

--
+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+--------------------------------------------------------------+
+ e-mail: macro@ds2.pg.gda.pl, PGP key available +

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