Subject: NOTE: interrupt handling changes on most desktop platforms
To: None <>
From: Charles M. Hannum <>
List: port-alpha
Date: 07/02/2004 12:58:02
Yesterday I checked in a change that fixes a 9 year old bug in
interrupt handling on most PCI-based desktop platforms (anything which
has a "sio" device).  I believe this bug was the source of the "common
wisdom" that Multias "need" level-triggered interrupts, among other
things -- after fixing it, my Multia works just fine with
edge-triggered interrupts, including PCMCIA.

Please test this on any relevant machines you have and let me know the

Module Name:    src
Committed By:   mycroft
Date:           Thu Jul  1 18:46:49 UTC 2004

Modified Files:
        src/sys/arch/alpha/pci: sio_pic.c

Log Message:
Fix a really old ("since day one") bug: send specific EOIs to the PIC, not
non-specific EOIs.  This really shouldn't matter so much, but I'm guessing
there's a strange interaction with the PALcode (possibly related to the fact
that the PALcode itself may be sending an EOI itself on some systems).

I have tested this on a Multia, and it appears to work just fine without the
INITIALLY_{ENABLED,LEVEL_TRIGGERED}() stuff now, so I'm also removing that.