Since the kernel 2.6.31-rc2 the i2c-viapro module is broken due to ACPI.
[ 284.901274] ACPI: I/O resource vt596_smbus [0x500-0x507] conflicts with ACPI region SMB1 [0x505-0x506]
[ 284.901286] ACPI: Device needs an ACPI driver
[ 284.901302] vt596_smbus: probe of 0000:00:11.0 failed with error -16
I think the problem is due to ACPI. In fact, code of the i2c-viapro didn't change between 2.6.31-rc1 and 2.6.31-rc2 and it worked in 2.6.31-rc1 but not in all the more recent others.
I'm a simple user, not a developer but i need to use the i2c/smbus of my machine.
*** This bug has been marked as a duplicate of bug 13939 ***