Re: New conflict message in latest GIT

[Fabio Comolli]

Hi.

On Wed, Jul 23, 2008 at 8:56 PM, Bjorn Helgaas <bjorn.helgaas@xxxxxx> wrote:
> On Tuesday 22 July 2008 12:56:36 pm Fabio Comolli wrote:
>> Linus' GIT tree 2.6.26-05752-g93ded9b shows this message:
>>
>> i801_smbus 0000:00:1f.3: PCI INT B -> GSI 19 (level, low) -> IRQ 19
>> ACPI: I/O resource 0000:00:1f.3 [0x18e0-0x18ff] conflicts with ACPI
>> region SMBI [0x18e0-0x18ef]
>> ACPI: Device needs an ACPI driver
>>
>> There is no equivalent in 2.6.26 or previous kernels.
>
> The "ACPI: I/O resource ... conflicts with ..." message was added by
> Thomas:
>  http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=df92e695998e1bc6e426a840eb86d6d1ee87e2a5
>
> That conflict checking infrastructure was in 2.6.26, but Jean's
> change to make the i801_smbus driver use it didn't happen until
> about a week ago:
>  http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=54fb4a05af0a4b814e6716cfdf3fa97fc6be7a32
>
> The message is telling us that the i801_smbus driver thinks it owns
> the 0x18e0-0x18ff region, but there's also an ACPI opregion that
> references that region.  There's no coordination between ACPI and
> the i801_smbus driver, so there may be issues where nearly
> simultaneous accesses cause incorrect behavior, e.g,. one may
> read the wrong value from a temperature sensor.  That, of course,
> can lead to more serious things like unintended machine shutdowns.
>
> I don't have any ideas about how to address this.  I think Thomas's
> intent was to collect better information for unreproducible bugs.
> (Maybe this sort of conflict should even set a taint flag?)
>

OK, I actually didn't even know what i801_smbus (i2c_801 I suppose)
was. It seems that my laptop has a super-IO chip which is detected by
lm-sensors as `Nat. Semi. PC87591 Super IO' which doesn't have a
driver and never will.

So, if I'm correct, this modules is totally useless for me and I
better compile it out. Am I correct?

> Bjorn
>
>

Regards,
Fabio
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