Re: kern/58684: mpii driver wedges during install of 10.0

[Havard Eidnes <he%NetBSD.org@localhost>]

Hm,

I see I didn't post an update to this, so here is one such.

"Behind the scenes" I got some hints which led me to being able
to resolve this problem.  At least in this particular case,
adjusting the number of outstanding requests to the "scsi"
controller (the drives are SAS, the controller also has RAID
functionality, but I use it in JBOD mode).

The dmesg (mis-labeled as RX2540, it's an RX2530) can be seen at

   https://dmesgd.nycbug.org/index.cgi?do=view&id=7934

and the SAS controller is identified as

[     1.062153] mpii0 at pci9 dev 0 function 0: Symbios Logic SAS3008 (rev. 0x02)
[     1.062153] mpii0: interrupting at msix7 vec 0
[     1.062153] mpii0: PSAS CP400i, firmware 16.0.0.0 IR, MPI 2.5

The change which made this system work was:

Index: sys/dev/pci/mpii.c
===================================================================
RCS file: /cvsroot/src/sys/dev/pci/mpii.c,v
retrieving revision 1.29.6.1
diff -u -r1.29.6.1 mpii.c
--- sys/dev/pci/mpii.c  26 Oct 2023 15:11:02 -0000      1.29.6.1
+++ sys/dev/pci/mpii.c  28 Sep 2024 13:43:31 -0000
@@ -91,7 +91,7 @@
 #endif
 
 #define MPII_REQUEST_SIZE              (512)
-#define MPII_REQUEST_CREDIT            (128)
+#define MPII_REQUEST_CREDIT            (64)    /* Was: 128 */
 
 struct mpii_dmamem {
        bus_dmamap_t            mdm_map;

An earlier attempt at going just down to 100 did not resolve the
problem, it merely postponed the wedge of the IO to a bit later
stage in the set extraction process during the installation.

The obvious question is whether we should apply this as a
workaround or fix or whether more analysis is required before
doing so.

It would be nice being able to install plain 10.1 once that's
released on this kind of systems...

Best regards,

- Havard