ia64/147502: [ia64][busdma] bounce buffering does not work reliably

[Marcel Moolenaar]

>Number:         147502
>Category:       ia64
>Synopsis:       [ia64][busdma] bounce buffering does not work reliably
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    freebsd-ia64
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sat Jun 05 17:20:03 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator:     Marcel Moolenaar
>Release:        9-CURRENT
>Organization:
>Environment:
FreeBSD hob.lan.xcllnt.net 9.0-CURRENT FreeBSD 9.0-CURRENT #1 r208634:208809M: Sat Jun  5 08:36:47 PDT 2010     marcel at hob.lan.xcllnt.net:/usr/obj/nfs/freebsd/base/head/sys/HOB  ia64

>Description:
When running pho's stress2 on a machine with 8GB of RAM, bge(4) becomes non-functional. Eliminating all memory above 4GB and thereby eliminating the need to do bounce buffering results in a "successful" run.
>How-To-Repeat:
On a machine with bge(4) and memory located above 4G:
o   checkout projects/stress2
o   compile and run
o   Wait for the network to become non-functional
o   Abort the test and observe that the I/F remains non-functional
o   Flap the I/F (bring it down and then up) and see that it remains non-functional

Non-functional in this context means that no packets go out and none come in.

>Fix:
swi_vm() has been castrated so that busdma_swi() isn't being called. This may be all there is to it (i.e. remove the #if 0 and #endif)...


>Release-Note:
>Audit-Trail:
>Unformatted: