Odd piixpm behavior

[Paul Goyette <paul%whooppee.com@localhost>]

While trying to look into another problem (with the sdtemp(4) modular 
driver), I noticed something rather strange...

I have three systems with different but similar ASUS motherboards:

        M4A88T-M            AMD 880G / SB710
        M4A88TD-M           AMD 880G / SB850
        M4A88TD-V EVO/USB3  AMD 880G / SB850

Under NetBSD 5.99.55, the i2c bus was disabled:

        piixpm0 at pci0 dev 20 function 0
        piixpm0: vendor 0x1002 product 0x4385 (rev. 0x41)
        piixpm0: SMBus disabled

Under NetBSD 5.99.59, it gets probed normally:

        piixpm0 at pci0 dev 20 function 0
        piixpm0: vendor 0x1002 product 0x4385 (rev. 0x41)
        iic0 at piixpm0: I2C bus

Yet under NetBSD 5.99.60, it once again is disabled!


Clues?


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