amd64/144551: ACPI issues on SuperMicro X7SPA-H

Dan Naumov dan.naumov at
Mon Mar 8 16:40:22 UTC 2010

The following reply was made to PR amd64/144551; it has been noted by GNATS.

From: Dan Naumov <dan.naumov at>
To: bug-followup at
Subject: Re: amd64/144551: ACPI issues on SuperMicro X7SPA-H
Date: Mon, 8 Mar 2010 18:39:04 +0200

 OK, now I feel a bit stupid. The second half of my PR (anything
 related to powerd behaviour) can be ignored. For testing purposes, I
 started powerd in the foreground and observed it's behaviour. It works
 exactly as advertised and apparently the very act of issuing a "sysctl
 -a | grep dev.cpu.0.freq" command uses up a high % of CPU time for a
 fraction of a second, resulting in confusing output, I was always
 getting the highest cpu frequency state as the output. Testing powerd
 in foreground however, shows correct behaviour, CPU is downclocked
 both before and after issuing that command :)
 Still doesn't explain why the system boots up at 1249 Mhz, but that's
 not that big of an issue at this point now I see that powerd is
 behaving correctly.
 - Sincerely,
 Dan Naumov

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