Patch: sym(4) "VTOBUS FAILED" panics on amd64, amd64/89550

[Jan Mikkelsen]

Hi,

I posted this to freebsd-amd64, but I've had no replies.

This fixes the sym "VTOBUS FAILED" panics that I got consistently on
6.1-RELEASE/amd64;  see the PR amd64/89550 for dmesg, other reports, etc.

Quick summary:  sym(4) assumes on amd64 that virtual addresses provided by
bus_dmamem_alloc() have the same alignment as the physical addresses (in
this case, 2*PAGE_SIZE).  They don't, and stuff breaks.  This patch works
around that.

I'm looking for someone to take a quick look at it and make sure that the
approach is reasonable.  I would be nice if a fix was committed (not
necessarily mine).

sym(4) is listed as supported in the 6.1/amd64 hardware guide, but it
doesn't seem to be working at all.  For 6.2, I either suggest putting in a
fix so that it is supported, or having a note in the hardware guide.

Sorry about coming along so late in the release cycle, but I first
encountered the problem on Monday.

Thanks,

Jan Mikkelsen
-------------- next part --------------
A non-text attachment was scrubbed...
Name: sym_hipd.diff
Type: application/octet-stream
Size: 4672 bytes
Desc: not available
Url : http://lists.freebsd.org/pipermail/freebsd-stable/attachments/20060921/edcadeab/sym_hipd.obj