Commit d61a3ead ("[PATCH] IPMI: reserve I/O ports separately")
changed the way I/O ports were reserved and includes this comment in
log:

 Some BIOSes reserve disjoint I/O regions in their ACPI tables for the IPMI
 controller.  This causes problems when trying to register the entire I/O
 region.  Therefore we must register each I/O port separately.

There is a similar problem with memio regions on an arm64 platform
(AMD Seattle). Where I see:

 ipmi message handler version 39.2
 ipmi_si AMDI0300:00: probing via device tree
 ipmi_si AMDI0300:00: ipmi_si: probing via ACPI
 ipmi_si AMDI0300:00: [mem 0xe0010000] regsize 1 spacing 4 irq 23
 ipmi_si: Adding ACPI-specified kcs state machine
 IPMI System Interface driver.
 ipmi_si: Trying ACPI-specified kcs state machine at mem \
          address 0xe0010000, slave address 0x0, irq 23
 ipmi_si: Could not set up I/O space

The problem is that the ACPI core registers disjoint regions for the
platform device:

e0010000-e0010000 : AMDI0300:00
e0010004-e0010004 : AMDI0300:00

and the ipmi_si driver tries to register one region e0010000-e0010004.

Based on a patch from Mark Salter <msalter@redhat.com>, who also wrote
all the above text.
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Tested-by: Mark Salter <msalter@redhat.com>