From owner-freebsd-i386@FreeBSD.ORG Thu Oct 23 22:32:51 2003 Return-Path: Delivered-To: freebsd-i386@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id B8A2F16A4B3; Thu, 23 Oct 2003 22:32:51 -0700 (PDT) Received: from mailman.zeta.org.au (mailman.zeta.org.au [203.26.10.16]) by mx1.FreeBSD.org (Postfix) with ESMTP id C875D43FEA; Thu, 23 Oct 2003 22:32:49 -0700 (PDT) (envelope-from bde@zeta.org.au) Received: from gamplex.bde.org (katana.zip.com.au [61.8.7.246]) by mailman.zeta.org.au (8.9.3p2/8.8.7) with ESMTP id PAA01066; Fri, 24 Oct 2003 15:29:37 +1000 Date: Fri, 24 Oct 2003 15:28:15 +1000 (EST) From: Bruce Evans X-X-Sender: bde@gamplex.bde.org To: Rolf Witt In-Reply-To: <200310231727.h9NHRMvN082838@peanuts.homeunix.org> Message-ID: <20031024152337.B8637@gamplex.bde.org> References: <200310231727.h9NHRMvN082838@peanuts.homeunix.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII cc: FreeBSD-gnats-submit@FreeBSD.org cc: freebsd-i386@FreeBSD.org Subject: Re: i386/58458: ATAPI-CDROM DMA Support on ALi Aladdin V Chipset is brocken X-BeenThere: freebsd-i386@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: I386-specific issues for FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Oct 2003 05:32:51 -0000 On Thu, 23 Oct 2003, Rolf Witt wrote: > >Description: > If DMA on IDE-Channel 1 Device 0 aktiv, the DVD-ROM Drive no more works. > Only PIO works. I have testet this with 2 Drive (both have UDMA33 ability). > On Pre 4.8 Releases it still functioned. I forwarded the following usenet article to the author of the bug, but received no reply. % Date: Mon, 13 Oct 2003 08:07:01 +0000 (UTC) % From: viro@parcelfarce.linux.theplanet.co.uk % Newsgroups: comp.unix.bsd.freebsd.misc % Subject: Re: Linux vs. FreeBSD (supportability) % % In article <3f8a362c$1_2@corp.newsgroups.com>, % Donn Miller wrote: % % >I've had problems with filesystem corruption with both ext2 and ext3, % >but never ext3. % % Count the bug reports and see. Most of the cases of fs corruption % turn out to be either random memory corruption or breakage in underlying % block device driver. Neither of those cares about fs type, obviously. % % If you have real cases of ext2 corruption (not of these two classes and not % "I had a dirty shutdown and fsck complained about something, I don't remember % what") - post a bug report. % % > I think ext2 is the most crude and cruddy hack of a % >filesystem ever created. ReiserFS is clearly the best filesystem for % >Linux right now. % % % % >Sounds like he must've been compiling his world and kernel with -O3 % >-fomit-frame-pointer -fthread-jumps -funroll-all-loops % >-fstrength-reduce again. Believe it or not, the default Gentoo % >optimization flags were along the same lines at one time. The Linux % >kernel seemed more forgiving in the past of such idiotic optimization % >levels, but I think he might be getting "more lucky" with Linux in such % >a situation. Even knowledgeable Linux people will advise against % >building the kernel with such insane optimizations. % % FWIW, that sort of bugs tend to boil down to missing memory barrier or % missing lock. Not that gcc was too tolerant to anything past -O2, but % more often than not the real problem is in the code. BTDT... % % Idiocy happens. Case in point: while digging through ata-dma.c in 4.9-RC % a couple of hours ago, I've found the following gem: % % switch(ATA_PIO0 + apiomode) { % case ATA_PIO0: timing = 0x006d0003; % case ATA_PIO1: timing = 0x00580002; % case ATA_PIO2: timing = 0x00440001; % case ATA_PIO3: timing = 0x00330001; % case ATA_PIO4: timing = 0x00310001; % default: timing = 0x006d0003; % } % % (M5229 support, in case you wonder and no, -CURRENT doesn't have that bug). % Had been there for quite a while and that's exactly the sort of bug that % is harder to find. I'd seen equivalents blamed on compiler, OS, hardware, % admin, yadda, yadda. Usually ends up with massive blushing when you % finally realize that yes, it was _that_ dumb... % % Bruce