X570 AORUS Master SMBus missing / conflicted under Linux

[rexar]

X570 AORUS Master Rev 1.0 Bios F10 under Opensuse Tumbleweed w/ kernel 5.4.2.

I’m curious to know if anyone using any of Gigabyte’s X570 boards running Linux are able to see their CPU/chipset SMBus adapter with the i2c_piix4 driver?

What got me interested was that decode-dimms failed to detect anything and a run of ‘i2cdetect -l’ failed to reveal any controllers. When i2c-dev is enabled only the GPU buses are detected which doesn’t help.

I’m expecting i2cdetect’s output to be similar to the first response to this issue here (noting it is an Asus A75 board).

i2c-piix4 driver on Linux does not see AMD X370's 0x0B20 bus, performance is...

Particularly (for example)
i2c-0 smbus SMBus PIIX4 adapter port 0 at 0b00 SMBus adapter
i2c-4 smbus SMBus PIIX4 adapter port 1 at 0b20 SMBus adapter

But alas, nothing.

I am suspecting there is an ACPI conflict occurring as this message coincidentally appears when the i2c_piix4 module is probed in dmesg

[   16.762700] ACPI Warning: SystemIO range 0x0000000000000B00-0x0000000000000B08 conflicts with OpRegion 0x0000000000000B00-0x0000000000000B0F (\GSA1.SMBI) (20190816/utaddress-204)

Which matches the regular address range of the SMBus controller. This happens regardless of ACS/CSM/TBT settings in the bios.

So before diving further in, can anyone else see their X570 CPU/chipset SMBus adapter under Linux?

[Vim]

You can make modules ignore ACPI conflicts with the kernel parameter acpi_enforce_resources=lax.

I have an old ASUS motherboard which presents the exact same issue, with same conflict messages, and setting this parameter allowed i2c_piix4 to succesfully load and i2cdetect to correctly list the SMBus adapters.

According to the old lm-sensors webpage at http://web.archive.org/web/20140630034601/http://www.lm-sensors.org/wiki/FAQ/Chapter3#Mysensorshavestoppedworkinginkernel2.6.31, using acpi_enforce_resources=lax could be pretty dangerous if some ACPI driver is also trying to access the chip at the same time, so caveat emptor.