kern/45034: Satalink driver downgrades from DMA to PIO 4 from soft errors (sandpoint/PowerPc)

[oscarmolin%gmail.com@localhost]

>Number:         45034
>Category:       kern
>Synopsis:       Satalink driver downgrades from DMA to PIO 4 from soft errors 
>(sandpoint/PowerPc)
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Jun 09 15:00:00 +0000 2011
>Originator:     Oscar Molin
>Release:        NetBSD 5.99.52 (GENERIC) #0: Sun May 29 10:35:38 UTC 2011
>Organization:
>Environment:
NetBSD netcube 5.99.52 NetBSD 5.99.52 (GENERIC) #0: Sun May 29 10:35:38 UTC 
2011  
builds%b8.netbsd.org@localhost:/home/builds/ab/HEAD/sandpoint/201105290240Z-obj/home/builds/ab/HEAD/src/sys/arch/sandpoint/compile/GENERIC
 sandpoint
>Description:
When performing large file transfers (tested over NFS) onto harddrives attached 
to silicon image 3512 controller, soft errors occur and causes the satalink 
driver to downgrade from DMA to PIO 4 mode, causing big performance penalty.

This has been tested with all for available SATA channels (my system has  
2x2-port controllers) and with different harddrives and SATA cables.

After rebooting, the harddrives function at full speed again but when large 
transfers are started, soft errors occur after a short while.

No data corruption ever occurs, and the problem doesn't appear under Linux.
>How-To-Repeat:
Transfer large file to harddrive over NFS (probably other means aswell)
>Fix: