Subject: BT946C support -- maybe I _am_ an idiot?
To: None <port-i386@sun-lamp.cs.berkeley.edu, current-users@sun-lamp.cs.berkeley.edu>
From: Thor Lancelot Simon <tls@panix.com>
List: current-users
Date: 08/29/1994 21:31:32
Many motherboards seem to ship with all the PCI interrupts switched off.

Incredibly enough, the BT946 will boot DOS and even some Unixes in this
condition.  To make it work correctly, the "PIN" setting in the "Auto-SCSI"
adapter BIOS has to be set to the letter of the PCI INterrupt (ever wonder
what PIN stood for?  Nice that the BT946 manual documents it, huh?) that your
motherboard's BIOS has set to the same IRQ number as the board's slot.

That sounds somewhat complex, but that's what appears to work, and I can't
seem to find a better way to simplify it.

If you still can't get it to work, try turning off some of the PCI caches your
chipset may provide.  Of course, most motherboards ship with *those* turned
off, too, but who knows?  My motherboards actually seem to work OK modulo
coming from the manufacturer in a really stupid configuration.  When will
people learn that turning off features can sometimes make hardware *less*
compatible?

Of the three different kinds of PCI motherboards I tested today, *none* worked
right with their default settings or the recommended settings from their
alleged "manuals".  Two seemed to work okay once I learned what parts of the
manual I had to ignore completely.

PCI autoconfiguration.  heh.

Could the kernel autodetect some of this stuff?  Where do I get a copy of the
PCI spec?  The number I have for Intel's PCI group seems to be no longer in
service...

Hope this is helpful to someone.

Thor

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