Date: Sun, 31 Mar 2013 00:29:51 +0100 From: Matthias Andree <mandree@FreeBSD.org> To: freebsd-stable@freebsd.org Cc: Alexander Motin <mav@FreeBSD.org>, freebsd-current@freebsd.org Subject: Re: Any objections/comments on axing out old ATA stack? Message-ID: <5157756F.4040908@FreeBSD.org> In-Reply-To: <51536306.5030907@FreeBSD.org> References: <51536306.5030907@FreeBSD.org>
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This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig338DC6674EB2008BF0825764 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Am 27.03.2013 22:22, schrieb Alexander Motin: > Hi. >=20 > Since FreeBSD 9.0 we are successfully running on the new CAM-based ATA > stack, using only some controller drivers of old ata(4) by having > `options ATA_CAM` enabled in all kernels by default. I have a wish to > drop non-ATA_CAM ata(4) code, unused since that time from the head > branch to allow further ATA code cleanup. >=20 > Does any one here still uses legacy ATA stack (kernel explicitly built > without `options ATA_CAM`) for some reason, for example as workaround > for some regression? Does anybody have good ideas why we should not dro= p > it now? Alexander, The regression in http://www.freebsd.org/cgi/query-pr.cgi?pr=3Dkern/15739= 7 where the SATA NCQ slots stall for some Samsung drives in the new stack, and consequently hang the computer for prolonged episodes where it is in the NCQ error handling, disallows removal of the old driver. (Last checked with 9.1-RELEASE at current patchlevel.) Chances are that limiting the open queue slots to 31 might help, but that is hearsay from what Linux would be doing. Unless we get a fix, if you want to drop the old driver, you'll need to add features so that 1. the new driver to lets users (down-)configure the max. number of tagged openings 2. the new driver allows disabling NCQ altogether for individual drives 3. list the relevant Samsung drives in some quirks data base so that we avoid the stalls while permitting users to "open it up to 32 NCQ slots". So unless these are all addressed, I'd veto removal of the old ATA driver - sorry! Best regards Matthias --------------enig338DC6674EB2008BF0825764 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with undefined - http://www.enigmail.net/ iEYEARECAAYFAlFXdW8ACgkQvmGDOQUufZVJ2ACg0eUnW4Xe5nVJo3zLTaYjUARG KcgAniDIIJ8oveV3YB5GV7sNTYc1+ar8 =2f7y -----END PGP SIGNATURE----- --------------enig338DC6674EB2008BF0825764--
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