From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 26 Jan 2001 12:22:29 -0500 From: Daniel Eisenbud To: Benjamin Herrenschmidt Cc: linuxppc-dev@lists.linuxppc.org Subject: Re: Fwd: mesh SCSI bus locks hard on 7500 when burning a CD-R in dao mode Message-ID: <20010126122229.B2874@allspice.cs.swarthmore.edu> References: <20010125165015.B15827@allspice.cs.swarthmore.edu> <19341221043908.3227@mailhost.mipsys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <19341221043908.3227@mailhost.mipsys.com>; from benh@kernel.crashing.org on Fri, Jan 26, 2001 at 12:07:24PM +0100 Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: on Fri, Jan 26, 2001 at 12:07:24PM +0100, Benjamin Herrenschmidt wrote: > >I have a Powermac 7500 (with a G3 accelerator.) I have replaced the > >internal CD-ROM with a Yamaha CD-RW drive. This sits on the mesh SCSI > >bus. I have the mesh driver configured to run at 5 megabytes/second > >(since I get massive SCSI problems all over the place if I set it to > >10.) Under a variety of kernels, from 2.2.15 or so to 2.4.0 from Paul > >Mackeras's tree, my SCSI setup is generally stable and I can burn CD-R > >disks just fine in track-at-once mode. However, if I try to burn a disk > >in disk-at-once mode, either with cdrdao or cdrecord, the SCSI bus > >appears to silently lock up hard, bringing down my whole machine. > >Nothing is logged at all, as far as I can tell. Has anyone had this > >problem before? Does anyone know of a solution? If not, how would I go > >about debugging this further? > > Do you see any kind of kernel error messages on the console before it > locks up ? Nope, nothing at all. :-( It just freezes. Since the SCSI bus is gone, any attempts to write to logs fail, as do any attempts to read them, of course. cdrdao gets to the "calibrating power" stage, the light on the cd-rw drive blinks for a few seconds, and that's it. Last time I tried this experiment, I at least turned swap off first, and the system survived a bit longer, but I wasn't able to find anything out. Is there any other way to probe what's going on? I do have a 2 gigabyte drive that I could attach to the external SCSI bus and boot from: maybe then I could get more info, at least, about what is going on. -Daniel -- Daniel E. Eisenbud eisenbud@cs.swarthmore.edu ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/