[659] in linux-scsi channel archive
Re: 53c825 dies w/o ftape's buffers? huh?
daemon@ATHENA.MIT.EDU (Kai Harrekilde-Petersen)
Wed Oct 4 22:07:21 1995
From: Kai Harrekilde-Petersen <khp@pip.dknet.dk>
To: mja@telecom.wisc.edu (Michael Adas)
Date: Wed, 4 Oct 1995 20:48:29 +0100 (MET)
Cc: linux-scsi@vger.rutgers.edu (Linux SCSI mailing list)
In-Reply-To: <Pine.LNX.3.91.951003192145.4465A-100000@venus.telecom.wisc.edu> from "Michael Adas" at Oct 3, 95 07:49:01 pm
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Michael Adas writes:
> The kernel recognizes scsi the card and functions perfectly if I enable
> QIC-117 support. All other drivers being the same, if I remove
> support for floppy tapes, the NCR dies on init. It genrally complains
> about an existing issue queue, followed by a slew of other errors. (I
> could write them down if need be.)
> Boot messages that looked relevant to me:
> (trimmed for brevity)
> ----working kernel, with ftape----
> ftape: allocated 3 buffers aligned at: 001e8000
> scsi-ncr53c7,8xx : at PCI bus 0, device 10, funtion 0
> scsi-ncr53c7,8xx : NCR53c825 at memory 0xfbfdf000, io 0xe400, irq 12
> scsi0 : NCR code relocated to 0x2002f0
> ----non-working kernel, removing ftape was the only change----
> scsi-ncr53c7,8xx : at PCI bus 0, device 10, funtion 0
> scsi-ncr53c7,8xx : NCR53c825 at memory 0xfbfdf000, io 0xe400, irq 12
> scsi0 : NCR code relocated to 0x1e3750
Sounds like you've got some buggy hardware ...
To quote from the ftape-HOWTO:
8.4. ftape DMA transfers gives ECC errors
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
(0xff). These problems are reported to happen with both SVGA and
ethernet cards. We know of at least one (bad?) ATI 16bit VGA card
that caused this.
The easiest solution is to put the card in an 8bit slot (it is often
not enough to reconfigure the card to 8bit transfers). Moving the
ftape buffer away from the VGA range is only a partial solution; All
DMA buffers used in Linux can have this problem! Let us make this one
clear: This has nothing to do with the ftape software.
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 <<
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