Re: [lm-sensors] Could the k8temp driver be interfering with ACPI?

From: Luca Tettamanti
Date: Tue Feb 20 2007 - 10:34:24 EST


On 2/20/07, Matthew Garrett <mjg59@xxxxxxxxxxxxx> wrote:
On Sun, Feb 18, 2007 at 06:38:05PM +0100, Jean Delvare wrote:

> ACPI is broken here, not k8temp, so let's fix ACPI instead. ACPI
> doesn't conflict with only k8temp, but with virtually all hardware
> monitoring drivers, all I2C/SMBus drivers, and probably other types of
> drivers too. We just can't restrict or blacklist all these drivers
> because ACPI misbehaves.

No, the simple fact of the matter is that if you're running on an ACPI
platform you need to change some of your assumptions. ACPI owns the
hardware. The OS doesn't. To an extent this has always been true on
laptops and servers /anyway/ - the BIOS is free to have a wide variety
of SMM insanity that invalidates basic assumptions like "If I hold this
lock, nothing can interrupt me between this write and this read". That's
simply not true.

So this isn't about fixing ACPI. It's about trying to find a mechanism
that allows ACPI and raw hardware drivers to coexist, which is made
somewhat harder by it not being a situation that the platform designers
have considered in the slightest.

Motherboard vendors usually provide tools for $(TheOtherOS) that can
read from all thermal / fan / voltage / whatever sensors, so I guess
it's possible to make the ACPI driver and the "raw" one play nice with
each other[1].

Luca
[1] Unless their solution is "poke at the hardware and hope that ACPI
doesn't blow up", that is.
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