ipr boot failure caused by MSI (2.6.30-rc1+)

[James Bottomley <James.Bottomley@HansenPartnership.com>]

Kernels after 2.6.30-rc1 stopped booting on my powerstation.  The ipr
just times out and refuses to probe devices.  If I let it drop into the
initramfs system, this is what the interrupts shows:

(initramfs) cat /proc/interrupts 
           CPU0       CPU1       CPU2       CPU3       
 16:         20         10         13         11   MPIC      Level     pata_amd
 20:          0          0          0          0   MPIC      Level     ohci_hcd:usb1, ohci_hcd:usb2
 21:          0          0          0          0  MPIC-U3MSI Edge      ipr
 68:         37         37         48         37   MPIC      Edge      serial
251:         10         71         69         72   MPIC      Edge      ipi call function
252:       1555       1779       1372       1155   MPIC      Edge      ipi reschedule
253:          0          0          0          0   MPIC      Edge      ipi call function single
254:          0          0          0          0   MPIC      Edge      ipi debugger
BAD:        416

So you see the IPR is the only device not receiving them.

I can fix the boot hang by reverting

commit 5a9ef25b14d39b8413364df12cb8d9bb7a673a32
Author: Wayne Boyer <wayneb@linux.vnet.ibm.com>
Date:   Fri Jan 23 09:17:35 2009 -0800

    [SCSI] ipr: add MSI support

The system in question is:

SYSTEM INFORMATION
 Processor  = PowerPC,970MP @ 2500 MHz
 I/O Bridge = U4 (4.4)
 SMP Size   = 4 (#0 #1 #2 #3)
 Boot-Date  = 2009-04-21 17:13:36
 Memory     = 2 GB of RAM @ 666 MHz
 Board Type = Bimini (7047191/0000000/1)
 MFG Date   = 1608
 Part No.   = 10N8748     
 FRU No.    = 10N7182     
 FRU Serial = YL30W8106038
 UUID       = 00000000000000000000000000000000
 Flashside  = 1 (temporary)
 Version    = HEAD
 Build Date = 12-04-2008 16:13

James