Date: Tue, 25 Mar 2008 12:19:17 +0100 From: Tektonaut <tektonaut@fuckner.net> To: remko@FreeBSD.ORG, freebsd-bugs@FreeBSD.ORG, sos@FreeBSD.ORG, Adam Pordzik <tektonaut@fuckner.net> Subject: Re: kern/121686: [ata]: bogus CHS to LBA mapping in (at least) ata Message-ID: <47E8DFB5.1020503@fuckner.net> In-Reply-To: <20080324213323.GA87260@zim.MIT.EDU> References: <200803140710.m2E7A0IM079653@freefall.freebsd.org> <20080324213323.GA87260@zim.MIT.EDU>
next in thread | previous in thread | raw e-mail | index | archive | help
David Schultz wrote: > This is a problem with some CD-ROMs, too, except in the case of > CD-ROMs, the problem is more fundamental: the official standard > allows the drive to overestimate the disc's capacity by a few > sectors. Sounds like the drives are guessing the correct sector count... > GEOM just exacerbates the problem by having a dozen > different providers each try to read the last sector. The latter > issue has been discussed and the general reaction is that it's > undesirable to force GEOM providers to cope with misbehaving > devices. I can't see any problem here. Of course, GEOM should never try to work arounf hardware issues, imho. Nobody would argue against a disk with broken sector zero. > The fact that these errors result in a timeout in FreeBSD but not > under (at least) Solaris makes me wonder whether there isn't a > better way for the ata driver to notice the error than a timeout. > Then again, I'm not an expert on ata. Maybe. But here the last sector definitively is readable, e.g. I can access this CF-Card with da(4) via umass in a card-reader. As I understand ata-disk.c, it uses fixed and pre-defined values for heads and sectors/track to calculate overall cylinder count. Since this mapping also appears in ata-all.c, I have no idea where to fix it. (Didn't looked in ata-raid.c) Soren, did already you found some time to look at it? Why there is a need to "think" in CHS at all? Regards, Adam --
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?47E8DFB5.1020503>