[SOLVED] Re: I2C bus can not find sensors since kernel 2.6.18

[Wang Xu <gnawux@gmail.com>]

On Sun, Apr 29, 2007 at 12:59:33PM +0800, gnawux wrote:
> But under 2.6.18 and 2.6.20 kernel, no sensors could be found,
> I enable the debug option of 2.6.20 kernel, and found the following
> error message of i2c bus:
>  | PCI: Unable to reserve I/O region #5:20@e800 for device 0000:00:1f.3
>  | i801_smbus 0000:00:1f.3: Failed to request SMBus region 0xe800-0xe81f
>  | i801_smbus: probe of 0000:00:1f.3 failed with error -16

The problem has been finally resolved by modifying the ACPI DSDT.

I found that in /proc/ioports

 | e800-e81f : 0000:00:1f.3
 |  e800-e80f : motherboard

therefore, smbus driver is trying to allocate e800-e81f (0x20) as 
the hints from PCI bus, while the acpi driver `motherboard' had
only requested e800-e80f (0x10), which lead to cannot request 
successfully.

Thus, I dumped the dsdt table and checked it, and modify

    Name (SMBS, 0xE800)
	Name (SMBL, 0x10)

to

    Name (SMBS, 0xE800)
	Name (SMBL, 0x20)

with iasl. then integrate the DSDT with initramfs. Everything
become well and do not need change kernel source anymore except
for the customized dsdt patch.

I also upload the customized DSDT table for ASUS M2400Ne laptop
to acpi.sf.net:

	http://acpi.sourceforge.net/dsdt/view.php?id=787

Cheers!

Wang Xu