Hi, I have converted both i2c-piix4 and sp5100_tco to use request_muxed_region() and use it instead of request_region(). The mutex lock / unlock around port I/O accesses in i2c-piix4 were replaced by request_muxed_region() / release_region(), it works in a similar way.
The same treatment was added to sp5100_tco. I sent the patch to two bugzillas: https://bugzilla.kernel.org/show_bug.cgi?id=170741 https://bugzilla.redhat.com/show_bug.cgi?id=1406844 It works for me, please test it. Best regards, Zoltán Böszörményi