cvs commit: src/etc/defaults rc.conf

[Nate Lawson]

Kris Kennaway wrote:
> On Sun, Jan 29, 2006 at 01:06:54AM -0500, Kris Kennaway wrote:
> 
>>On Sun, Jan 29, 2006 at 05:51:58AM +0000, Nate Lawson wrote:
>>
>>>njl         2006-01-29 05:51:58 UTC
>>>
>>>  FreeBSD src repository
>>>
>>>  Modified files:
>>>    etc/defaults         rc.conf 
>>>  Log:
>>>  Enable the lowest Cx state by default.  This will save power and we have
>>>  had enough testing of acpi_cpu to know this is stable now.
>>
>>On my desktop system (running RELENG_6 though), setting
>>hw.acpi.cpu.cx_lowest=C0 causes atrocious performance.  Is it broken
>>in 6.x?
> 
> C2, sorry.

Ah, C0 should be disallowed already I thought (try it).

As for C2, I MFCd a patch to acpi_cpu.c in November that should prevent 
this (1.57.2.1).  Do you get a printf on console?

Commit msg:

If we're trying to use C2/3 and reads from the register are returning
immediately, back off to the next higher Cx sleep state.  Some machines
with a Via chipset report a valid C3 but a register read doesn't 
actually halt the CPU.  This would cause the machine to appear 
unresponsive as it repeatedly called cpu_idle() which immediately 
returned.  Causing interrupts (i.e. by pressing the power button) would 
cause the system to make forward progress, showing that it wasn't 
actually hung.

Also, enable interrupts a little earlier.  We don't need them disabled 
to calculate the delta time for the read.

-- 
Nate