Re: sg regression in 2.6.16-rc5

[Linus Torvalds <torvalds@osdl.org>]

On Fri, 3 Mar 2006, Steve Byan wrote:
> 
> On Mar 1, 2006, at 1:42 PM, Linus Torvalds wrote:
> > 
> > I wouldn't expect it to. Most people use ATA for that, and it tends to
> > have lower limits than most SCSI HBA's (well, at least the old PATA), so
> > the change - if any - should at most change some of the sg.c limits to be
> > no less than what SG_IO has had on ATA forever.
> > 
> > Not that I expect people to have a SCSI CD/DVD drive anyway in this day
> > and age, so the sg.c changes probably won't show up at all.
> 
> CD-ROM support is a frequently-requested feature on the iSCSI Enterprise
> Target (iet) email list. It won't be long before iSCSI CD and DVD devices
> start showing up, although the underlying hardware will be ATAPI or else
> missing entirely (i.e. ISO image file).

Yes, but the point that the ATA limits tend to be on the low side still 
stands.

For example, I think the IDE driver defaults to a maximum transfer of 256 
sectors, and the same number of max scatter-gather entries. Some 
controllers will actually lower that, due to silly hw problems.

The point being that it has worked fine for IDE, and if a SCSI controller 
has noticeably lower limits than that, there's something really strange 
going on, like a real bug.

			Linus
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/