[663] in linux-scsi channel archive
Re: 53c825 dies w/o ftape's buffers? huh?
daemon@ATHENA.MIT.EDU (Kai Harrekilde-Petersen)
Thu Oct 5 20:49:57 1995
From: Kai Harrekilde-Petersen <khp@pip.dknet.dk>
To: mja@telecom.wisc.edu (Michael Adas)
Date: Thu, 5 Oct 1995 18:14:08 +0100 (MET)
Cc: linux-scsi@vger.rutgers.edu (Linux SCSI mailing list)
In-Reply-To: <Pine.LNX.3.91.951004224010.5468A-100000@venus.telecom.wisc.edu> from "Michael Adas" at Oct 4, 95 10:50:02 pm
-----BEGIN PGP SIGNED MESSAGE-----
Michael Adas writes:
> On Wed, 4 Oct 1995, Kai Harrekilde-Petersen wrote:
> > Sounds like you've got some buggy hardware ...
> >
> > Sadly to say there are some SVGA cards and ethernet cards that do not
> > decode their addresses correct. This typically happens when the ftape
> > buffers are in the range 0x1a0000 to 0x1c0000. Somehow, the DMA write
> > cycles get clobbered and every other byte written gets a bad value
> The way this is written implies (to me) that using ftape can cause
> problems with some errant hardware. My machine dies when i *dont'*
> include ftape. I don't have one of the these nasty drives, but my
> machine doesn't work unless I turn on CONFIG_FTAPE. This is annoying
> in that the only thing CONFIG_FTAPE does is allocate an extra 96k on
> bootup.
OK. What I meant was: you are probably seeing the above problem. The
*cause* of the problem has nothing to do with ftape; ftape is just
unlucky to get bitten (too).
It appears to me that you are bitten, since you have (NCR scsi) dma
buffers in the "dangerous" 0x1a0000 to 0x1c0000 range (like some ftape
users). When you add CONFIG_FTAPE, the ftape buffers will occupy the
troublesome range, and thus moving your SCSI dma buffers of out the
"danger zone". If you _did_ have a tape drive, you would see
corruption of data on the tape drive.
Kai
- --
Kai Harrekilde-Petersen <khp@pip.dknet.dk> Linux: choice of a GNU generation
>> Inside every little problem there's a BIG problem, struggling to get out <<
PGP Key fingerprint = F6 33 E0 4E 01 17 85 8C 4F 7F 1F F8 14 E7 86 1D
-----BEGIN PGP SIGNATURE-----
Version: 2.6.2
iQCVAgUBMHQSW+IL8NbSzfiVAQGn4AP9H8NsU5lKFA0vGXGD20wQ0bosB6LywUuV
yvhRHg1SV+2g1AUh0uBvdFXmuDoc1g6Z8Bbmf2L/BzZaE+vylcH05qjdiIbVaP1x
M8LIxa+paotgWu+N4E0jwDE/gWWXGPHgZl2c/XJwdW6tYzZ7AF7z9uxdlNndEb6p
EF5sPzxcx/k=
=uD6m
-----END PGP SIGNATURE-----
