ACPI blocking I2C driver - Poulsbo

ACPI blocking I2C driver - Poulsbo

[simon]

Hi all,
I am chasing a problem on a Poulsbo based board where the ACPI subsystem
is blocking a chunk of memory and preventing the Poulsbo I2C driver
loading.

> --
> [  403.809826] ACPI: resource (null) [io  0x0480-0x04bf] conflicts with
> ACPI region PHO_ [io 0x4bc-0x4bc]
> [  403.809834] ACPI: If an ACPI driver is available for this device, you
> should use it instead of the native driver
> [  403.809921] lpc_sch: probe of 0000:00:1f.0 failed with error -16
> --

If I boot with 'acpi=off' kernel option, then I2C can function as expected.

As far as I can see there is no reason why ACPI should be holding onto
this address block, this block is shown in '/proc/ioports' but no driver
listed.

The board also contains a IET IT8516 SuperIO which interfaces to the
charger/batteries/etc.

dmidecode and acpidump logs under the original posting:
http://thread.gmane.org/gmane.linux.drivers.i2c/8154/focus=8171

Thanks in advance,
Simon.

Re: ACPI blocking I2C driver - Poulsbo

[Matthew Garrett]

On Wed, Apr 06, 2011 at 11:02:23AM -0400, simon@mungewell.org wrote:

> > [  403.809826] ACPI: resource (null) [io  0x0480-0x04bf] conflicts with
> > ACPI region PHO_ [io 0x4bc-0x4bc]
> > [  403.809834] ACPI: If an ACPI driver is available for this device, you
> > should use it instead of the native driver
> > [  403.809921] lpc_sch: probe of 0000:00:1f.0 failed with error -16

Your DSDT contains:

    OperationRegion (PHO, SystemIO, 0x04BC, One)

We won't touch the same region because of the risk of races between the 
firmware and the kernel. Boot with acpi_enforce_resources=lax if you 
think it's safe. Alternatively, if the i2c driver doesn't need the 0x4bc 
address, fix it not to request it.

-- 
Matthew Garrett | mjg59@srcf.ucam.org