Date: Sun, 24 Sep 2006 08:40:34 +1000 From: "Jan Mikkelsen" <janm@transactionware.com> To: "'Stefan Esser'" <se@FreeBSD.org>, "'Scott Long'" <scottl@samsco.org> Cc: freebsd-stable@freebsd.org Subject: RE: Patch: sym(4) "VTOBUS FAILED" panics on amd64, amd64/89550 Message-ID: <001701c6df61$48504640$0202a8c0@transactzbkv04> In-Reply-To: <4514206A.8030601@FreeBSD.org>
next in thread | previous in thread | raw e-mail | index | archive | help
Stefan Esser wrote: > I've been the co-author of the ncr SCSI driver, on which sym is based > (though not that particular code fragment). Since I know the structure > and principals of the driver (and since I have and know the docs up to > the 53c875, possibly also the 53c895), I'd probably be in a position > to work on this with the least effort to get started. Only problem is > that I do not have an amd64 system for testing ... >=20 > I changed the private allocator in the sym driver to use contigmalloc, > some time ago, but now I understand that there are stricter alignment > requirements. For a start, a work-around could be committed,=20 > IMHO (even > if it is ugly). The better approach is of course an extension=20 > of busdma > to support aligned physical chunks as required by the driver. >=20 > But I could also try to find a clean fix for the affected driver code. What are the "stricter alignment requirements" you have seen? The only = ones I have seen are those on virtual addresses caused by the buddy = allocator. Replacing that would remove the virtual address alignment requirements, unless I've missed something else. Are there special physical alignment requirements that the driver is not currently meeting? > Is the Symbios SCSI controller still used that much that the effort > required for a "clean" fix is well spent? This is a broader question. For my immediate purposes, my patch and = wasting a few pages gets a functional tape drive, which is a reasonable tradeoff = to me. I don't know how anyone else feels. This does seem to have been = broken on amd64 for a while and I haven't seen a large number of messages complaining. However: I needed an inexpensive SCSI controller for a machine, looked = at the supported hardware list, and bought a sym(4) controller. It didn't work. I think either the driver or the supported hardware list should = be fixed; my preference is the driver. Regards, Jan.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?001701c6df61$48504640$0202a8c0>