kern/108581: [sysctl] sysctl: hw.acpi.cpu.cx_lowest: Invalid argument

[Bruce Cran]

On Fri, 20 Mar 2009 00:30:03 GMT
Daniel Dvořák <dandee at hellteam.net> wrote:

> The following reply was made to PR kern/108581; it has been noted by
> GNATS.
> 
> From: =?UTF-8?Q?Daniel_Dvo=C5=99=C3=A1k?= <dandee at hellteam.net>
> To: <bug-followup at FreeBSD.org>,
> 	<lars.stokholm at gmail.com>
> Cc:  
> Subject: Re: kern/108581: [sysctl] sysctl: hw.acpi.cpu.cx_lowest:
> Invalid argument Date: Fri, 20 Mar 2009 01:01:51 +0100
> 
>  This is a multi-part message in MIME format.
>  
>  ------=_NextPart_000_0007_01C9A8F7.746C4190
>  Content-Type: text/plain;
>  	charset="UTF-8"
>  Content-Transfer-Encoding: quoted-printable
>  
>  Hi acpi team,
>  =20
>  today I have installed fbsd 7.1R on one box with this relativly old =
>  error and I was surprised about results .. it is the same:
>  =20
>  # uname -a
>  FreeBSD X.Y.Z 7.1-RELEASE FreeBSD 7.1-RELEASE #0: Thu Jan  1
> 14:37:25 = UTC 2009
> root at logan.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  = i386
>  
>  # sysctl dev.cpu.0.cx_supported
>  dev.cpu.0.cx_supported: C1/0
>  
>  # sysctl hw.acpi.cpu.cx_lowest=3DC1
>  hw.acpi.cpu.cx_lowest: C1
>  sysctl: hw.acpi.cpu.cx_lowest: Invalid argument
>  =20
>  # sysctl hw.acpi.cpu.cx_lowest=3DC0
>  hw.acpi.cpu.cx_lowest: C1
>  sysctl: hw.acpi.cpu.cx_lowest: Invalid argument
>  =20
>  # sysctl hw.acpi.cpu.cx_lowest=3DC1/0
>  hw.acpi.cpu.cx_lowest: C1
>  sysctl: hw.acpi.cpu.cx_lowest: Invalid argument
>  
>  # dmesg -a | grep "acpi"
>  acpi0: <ASUS P4S8X-X> on motherboard
>  acpi0: Overriding SCI Interrupt from IRQ 9 to IRQ 20
>  acpi0: [ITHREAD]
>  acpi0: Power Button (fixed)
>  acpi0: reservation of 0, a0000 (3) failed
>  acpi0: reservation of 100000, ff00000 (3) failed
>  acpi_timer0: <24-bit timer at 3.579545MHz> port 0xe408-0xe40b on
> acpi0 acpi_button0: <Power Button> on acpi0
>  pcib0: <ACPI Host-PCI bridge> port 0xcf8-0xcff on acpi0
>  atkbdc0: <Keyboard controller (i8042)> port 0x60,0x64 irq 1 on acpi0
>  cpu0: <ACPI CPU> on acpi0
>  hw.acpi.cpu.cx_lowest:
>  hw.acpi.cpu.cx_lowest

I think I've found the problem and have updated the PR kern/108581
(http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/108581). The global
cpu_cx_count was being initialized to 0 in acpi_cpu_startup
(in /sys/dev/acpica/acpi_cpu.c) but code below it appears to assume that
it's been intialized to 3 because it only sets it if it's higher than
the current CPU supports - that is, cpu_cx_count should reflect the
highest Cx state that all CPUs support.

There's also a bug in the _CST section just below it; I think the line:

if (sc->cpu_cx_count > cpu_cx_count)

should be

if (sc->cpu_cx_count < cpu_cx_count)

-- 
Bruce Cran