FreeBSD 9.0 (RC2) Causes BIOS Message on Reboot

Andriy Gapon avg at
Wed Dec 14 22:14:27 UTC 2011

on 14/12/2011 22:20 Thomas D. Dean said the following:
> I know, this sounds strange.
> I have an ASUS P9X79 motherboard, Intel i7-3930K CPU.  The motherboard
> TPU switch is on.
> This overclocks the CPU to 4.162GHz.  Calculated from the TSC, with code
> from Intel.  The details of doing this are in the CPUID datasheet.
> sysctl dev.cpu.0 always shows freq as 3.201GHz no matter what the clock
> actually is.
> Often, when rebooting from FreeBSD, I get a message from BIOS that
> overclocking has failed - press F1 to enter setup.  I press F1, exit
> from setup, discarding changes, and the calculated CPU clock is
> 3.201GHz.  Overclocking has failed. 
> I shutdown, cycle power, boot, and overclocking works, calculated CPU
> clock is 4.162GHz.
> If I save changes when exiting from setup, overclocking works.  A bus
> reset is issued?
> I have a tripple boot, Windows 7 for possible warranty issues, Linux and
> FreeBSD 9.0(RC2).
> I never see this message when rebooting from either of the other two
> OS's, only FreeBSD.  I booted all three 5 times and saw 3 instances of
> overclocking failed when rebooting from FreeBSD.
> Here is the question:  How may I find out what is causing this?
> I have an HP Envy 17 3D notebook that always has side effects of booting
> FreeBSD 8.2 AMD64 where Windows 7 and Linux do not.  An over temperature
> message 0090D.  The machine is not actually over temperature, just
> something tweeked that BIOS sees.
> Two machines doing strange things on reboot - it is not hardware or
> BIOS, both different.

Just a hypothesis this might be caused by FreeBSD not following SMP spec
recommendation on the warm reboot procedure to the last letter.  Not sure how
you can verify that or fix that short of implementing the recommendations.

Andriy Gapon

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