Last two weeks I had been working on and off on a problem related to ACPI and some 1u servers using MSI-9618 motherboards. After booting freebsd, I couldn't get the second NIC to work at all, it turns out after looking at 'vmstat -i' that em0 and em1 where sharing an interrupt:

# vmstat -i
interrupt                          total       rate
irq3: sio1                      52807402         55
irq4: sio0                          1604          0
irq14: ata0                           36          0
irq16: em0 em1+                  2527378          2
irq19: uhci1+                      86991          0
cpu0: timer                   1886077214       2000
cpu1: timer                   1886076861       2000
Total                         3827577486       4058

From past experience I knew this was from poor resource assignment from the BIOS when ACPI isn't enabled. So I built and installed the acpi.ko modules and installed it. These are webware 1185s from pogolinux. The chassis manual that comes with it labels them as P1-103 series and a part number as MS-9218 1U rackmounts.

Then when I booted, right after it should be switching to multi-user, it appeared to hang. I enabled ALT_BREAK_TO_DEBUGER in the kernel and tried again, except the keycode for break to debugger did nothing. I posted about the hang on the freebsd-acpi list with no response. Then out of hand I tried sshing to the box... it worked! So it wasn't really hung, just the serial console was unresponsive.

Now looking closer at the dmesg I realized the resources for sio0 and sio1 were wrong! sio0 was getting 0x2F8 and sio1 was getting 0x3F8 when it should be the other way around. I rechecked the BIOS settings, everything was ok. I downloaded a new BIOS from the MSI taiwan site that stated the fix was for 'redhat 4' installs. That didn't work.

I posted to freebsd-acpi again with what I knew. This time I got a reply and after some back and forth, I generated a new .asl file that would probe sio0 and sio1 in the correct order! Now all my interrupts are assigned correctly:

[root@pogo-1 ~]# vmstat -i
interrupt                          total       rate
irq1: atkbd0                           6          0
irq3: sio1                      13587145         55
irq4: sio0                          1243          0
irq14: ata0                           36          0
irq16: em0 uhci3                    3237          0
irq17: em1                            21          0
irq19: uhci1+                      66550          0
cpu0: timer                    485520843       2000
cpu1: timer                    485520575       2000
Total                          984699656       4056

And everything seems to be working great, although my post's problem according to the resulting discussion on freebsd-acpi seems to be more common than imagined!