Date: Thu, 11 Nov 2010 11:33:03 +0100 From: Joerg.Schilling@fokus.fraunhofer.de (Joerg Schilling) To: mav@FreeBSD.org Cc: freebsd-scsi@FreeBSD.org, freebsd-current@FreeBSD.org, freebsd-stable@FreeBSD.org, marius@alchemy.franken.de Subject: Re: Sense fetching [Was: cdrtools /devel ...] Message-ID: <4cdbc65f.bo%2BmYNFB2GPwXmq7%Joerg.Schilling@fokus.fraunhofer.de> In-Reply-To: <4CDBC55B.1040307@FreeBSD.org> References: <4CD45209.5010607@FreeBSD.org> <20101105192028.GA68728@alchemy.franken.de> <4cd822df.o/wBtwsNCXiy8xZn%Joerg.Schilling@fokus.fraunhofer.de> <4CD82E2A.3070407@FreeBSD.org> <4cd8320a.U7/OjtLLBVtE4dTy%Joerg.Schilling@fokus.fraunhofer.de> <4CD83535.1010008@FreeBSD.org> <4cdbbfef.v4cr/k2jZr9gdpyF%Joerg.Schilling@fokus.fraunhofer.de> <4CDBC55B.1040307@FreeBSD.org>
next in thread | previous in thread | raw e-mail | index | archive | help
Alexander Motin <mav@FreeBSD.org> wrote:
> > The question still remains whether the previous implementation did return resid
> >> 0 in some cases. In this case, I would need to implement both variants in the
> > libscg adaption layer and I would need to know whether I am running on an old
> > version or on a new version kernel. Do you know of a simple method to implement
> > this distinction?
>
> Yes, some drivers were permanently reporting zero resid, while others
> (mostly real SCSI) were reporting proper values. Now it is the same,
> just more cases should work properly.
>
> Why do you want/need to distinguish them? You should already handle
> non-zero resid properly. Zero resid may be wrong in some cases, but at
> first I don't see fatal problem from it and at second I don't see what
> can you do about it.
>
> If I am missing something - sorry, explain it to me please.
Compare the number of sense bytes I like to request (18) with the number
previous FreeBSD versions did actually request. It is obvious that in case
there is a resid reported onm an old kernel, libscg (with your chanhge) would
believe that probably less that the absolute minumum of sense data is available.
Jörg
--
EMail:joerg@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
js@cs.tu-berlin.de (uni)
joerg.schilling@fokus.fraunhofer.de (work) Blog: http://schily.blogspot.com/
URL: http://cdrecord.berlios.de/private/ ftp://ftp.berlios.de/pub/schily
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4cdbc65f.bo%2BmYNFB2GPwXmq7%Joerg.Schilling>