Date: Thu, 26 Mar 2009 14:24:56 +0000 From: Bruce Cran <bruce@cran.org.uk> To: John Baldwin <jhb@freebsd.org> Cc: Daniel =?utf-8?Q?Dvo=C5=99=C3=A1k?= <dandee@hellteam.net>, freebsd-acpi@freebsd.org Subject: Re: kern/108581: [sysctl] sysctl: hw.acpi.cpu.cx_lowest: Invalid argument Message-ID: <20090326142456.042ea2f0@gluon.draftnet> In-Reply-To: <200903260937.51028.jhb@freebsd.org> References: <200903200030.n2K0U3iG011009@freefall.freebsd.org> <20090325223914.4387eeae@gluon.draftnet> <200903260937.51028.jhb@freebsd.org>
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On Thu, 26 Mar 2009 09:37:50 -0400 John Baldwin <jhb@freebsd.org> wrote: > On Wednesday 25 March 2009 6:39:14 pm Bruce Cran wrote: > > On Fri, 20 Mar 2009 00:30:03 GMT > > Daniel Dvo=C5=99=C3=A1k <dandee@hellteam.net> wrote: > >=20 > > > The following reply was made to PR kern/108581; it has been noted > > > by GNATS. > > >=20 > > > From: =3D?UTF-8?Q?Daniel_Dvo=3DC5=3D99=3DC3=3DA1k?=3D <dandee@helltea= m.net> > > > To: <bug-followup@FreeBSD.org>, > > > <lars.stokholm@gmail.com> > > > Cc: =20 > > > Subject: Re: kern/108581: [sysctl] sysctl: hw.acpi.cpu.cx_lowest: > > > Invalid argument Date: Fri, 20 Mar 2009 01:01:51 +0100 > > >=20 > > > This is a multi-part message in MIME format. > > > =20 > > > ------=3D_NextPart_000_0007_01C9A8F7.746C4190 > > > Content-Type: text/plain; > > > charset=3D"UTF-8" > > > Content-Transfer-Encoding: quoted-printable > > > =20 > > > Hi acpi team, > > > =3D20 > > > today I have installed fbsd 7.1R on one box with this relativly > > > old =3D error and I was surprised about results .. it is the same: > > > =3D20 > > > # uname -a > > > FreeBSD X.Y.Z 7.1-RELEASE FreeBSD 7.1-RELEASE #0: Thu Jan 1 > > > 14:37:25 =3D UTC 2009 > > > root@logan.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC =3D i386 > > > =20 > > > # sysctl dev.cpu.0.cx_supported > > > dev.cpu.0.cx_supported: C1/0 > > > =20 > > > # sysctl hw.acpi.cpu.cx_lowest=3D3DC1 > > > hw.acpi.cpu.cx_lowest: C1 > > > sysctl: hw.acpi.cpu.cx_lowest: Invalid argument > > > =3D20 > > > # sysctl hw.acpi.cpu.cx_lowest=3D3DC0 > > > hw.acpi.cpu.cx_lowest: C1 > > > sysctl: hw.acpi.cpu.cx_lowest: Invalid argument > > > =3D20 > > > # sysctl hw.acpi.cpu.cx_lowest=3D3DC1/0 > > > hw.acpi.cpu.cx_lowest: C1 > > > sysctl: hw.acpi.cpu.cx_lowest: Invalid argument > > > =20 > > > # 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 > >=20 > > I think I've found the problem and have updated the PR kern/108581 > > (http://www.freebsd.org/cgi/query-pr.cgi?pr=3Dkern/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. > >=20 > > There's also a bug in the _CST section just below it; I think the > > line: > >=20 > > if (sc->cpu_cx_count > cpu_cx_count) > >=20 > > should be > >=20 > > if (sc->cpu_cx_count < cpu_cx_count) >=20 > No, the code is doing things differently on purpose (though I'm not > completely sure why). For _CST it sets cpu_cx_count to the maximum > Cx level supported by any CPU in the system. For non-_CST it sets it > to the maximum Cx level supported by all CPUs in the system. I think > it is correct for cpu_cx_count to always start at 0 and only be > bumped up to a higher setting. Setting it to 3 would be very wrong > for the _CST case as I've seen CPUs that support C4. >=20 > Note that C1 _always_ exists as it is simply the "hlt" instruction > that has existed since the 8086. Only C2+ require power-saving > extension support in the CPU, so cpu_cx_count should always end up >=3D > 1. It would be interesting if you could add some debug printfs to > print out the values that acpi_cpu_generic_cx_probe() computes for > 'sc->cpu_cx_count' (sysctl dev.cpu could be useful for this) as well > as all changes to the 'cpu_cx_count' global variable. >=20 For my Athlon XP CPU, acpi_cpu_generic_cx_probe sets sc->cpu_cx_count to 1, and subsequently dev.cpu.0.cx_lowest has always worked. After adding printfs I found that the problem is that the cpu_cx_generic block in acpi_cpu_startup is being run and because cpu_cx_count is set to 0 it never gets updated; the statement "if (sc->cpu_cx_count < cpu_cx_count)" is never true. --=20 Bruce Cran
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