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Re: DECStation: Support for PMAZ-AA TC SCSI card?

To: Karel van Houten <>
Subject: Re: DECStation: Support for PMAZ-AA TC SCSI card?
From: "Maciej W. Rozycki" <>
Date: Wed, 17 Jul 2002 11:05:24 +0200 (MET DST)
Cc: "Houten K.H.C. van (Karel)" <>,
In-reply-to: <>
Organization: Technical University of Gdansk
Hi Karel,

> Usually I get SCSI bus problems when using the second chain.
> Even with devices that don't give any problems when connected to
> the on-board bus. Here is my boot log, with the scsi errors.
> In this case, I could use the disk on esp1, but I don't know
> if I can trust this...
> KN05 V2.1k
> >>cnfg
>  3: KN05     DEC      V2.1k    TCF0  (256 MB)
>                                      (enet: 08-00-2b-37-63-76)
>                                      (SCSI = 7)
>  1: PMAZ-AA  DEC      V5.3d    TCF0  (SCSI = 7)

 Well, you have a mixed system, so it's quite possible PMAZ-A support does
not work reliably anywhere.  I don't have such a card, but specs are
available and the support code is about one screen long.  So it should be
fairly trivial to verify -- I'll look at it. 

 Also you have a KN05 system, which doesn't help, unfortunately.  The KN05
module implements aggressive posting of uncached (read: iomem) writes (see
also /proc/interrupts on your system) and synchronization primitives are
non-existent.  Since for half a year there is no agreement on how generic
synchronization should look like for MIPS, I'm more and more tempted to
add a local hack which at least will let DECstations to perform reliably.
It's quite possible the lack of synchronization is the lone reason of your


+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+        e-mail:, PGP key available        +

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