mfi(4) patch to add MSI-X support, possibly address command timeouts

[David Wood]

Dear John (and freebsd-stable),

In message <201108311334.10804.jhb at freebsd.org>, John Baldwin 
<jhb at freebsd.org> writes
>I'd like some folks to test a patch to the mfi(4) driver that may help to
>address issues several folks have reported.  The patch does two things, first
>it adds some dummy reads of PCI registers when checking device status in the
>interrupt handler to "flush" the writes to ACK interrupts.  The Linux
>megaraid-sas driver uses this approach and some folks have tested a patch from
>Scott Long which had a somewhat similar effect.  Second, it enables the use of
>MSI-X interrupts for many newer devices.

I've installed this patch on my Dell PowerEdge 2950 III with a PERC 6/i 
controller, which is running 8.2-RELEASE. So far all is working well.

Is there any hope of MSI-X support for this device? It's 0x0060 - a 
SAS1078R - so is deliberately excluded from MSI-X by this patch. The 
system appears capable of MSI-X operation, but there might be a silicon 
bug I'm not aware of or extra code needed that is not provided by this 
patch.


With best wishes,




David
-- 
David Wood
david at wood2.org.uk