K 10
svn:author
V 8
kensmith
K 8
svn:date
V 27
2009-11-09T21:28:07.763641Z
K 7
svn:log
V 1193
MFC r198719 (head) r199095 (stable/8):
> While certain supported Symbios/LSI SCSI chips (532c896, 53c1000, 53c1010)
> do support 64bit addresses, the current SCRIPTS code supports only 32bit
> addresses causing data corruption for buffer addresses >4GB. This problem
> affects 64bit machines with more than 4GB RAM or amd64 with 4GB and
> memory hole remapping.
> Work-around this problem with a bus_dma tag that requests bounce-buffers
> for addresses >4GB. This causes some overhead, but given the maximum SCSI
> bus speed of 160MB/s compared, the effect should hardly be noticeable.
> The problem was reported by Mike Watters (mike at mwatters net) who also
> verified that this fix cures the problem.
>
> Since this change is a NOOP on systems with less than 4GB RAM and fixes
> data corruption (in RAM and on disk) on systems with more than 4GB, I hope
> that this change is accepted for 8.0.

Requested by: Stefan Esser (se at freebsd dot org)[1]
Reviewed by:  jhb, scottl

[1] Stefan requested this be part of 8.0 but has been unavailable to do
    the MFC since submitting the request.  We want to get 8.0-RC3 started
    so I'm doing the merges with re@ hat on.

Approved by:	re (bz)

END