Date: Fri, 21 May 1999 09:04:57 -0700 From: Mike Smith <mike@smith.net.au> To: Ladavac Marino <mladavac@metropolitan.at> Cc: "'Mike Smith'" <mike@smith.net.au>, Joel Ray Holveck <joelh@gnu.org>, Doug Rabson <dfr@nlsystems.com>, Peter Wemm <peter@netplex.com.au>, Tommy Hallgren <thallgren@yahoo.com>, freebsd-hackers@FreeBSD.ORG Subject: Re: Lazy SPLs Message-ID: <199905211604.JAA00852@dingo.cdrom.com> In-Reply-To: Your message of "Fri, 21 May 1999 10:07:24 %2B0200." <55586E7391ACD211B9730000C1100276179612@r-lmh-wi-100.corpnet.at>
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> > Level-triggered interrupts are persistent conditions, not queueable > > events. They typically require device-driver level intervention to be > > > > cleared. This is a major error in the PCI design (no surprises > > there). > > > [ML] Whoa there! That's the MAJOR advantage of PCI design. > Open collector, active low, level triggered interrupts are the only > possibility for interupt line sharing without programmatically > accessible registers on card which say "yes, I am still interrupting". For a simplistic bus, perhaps. But an arbitrated token-delivery interrupt buslet with a bus-standardised interrupt state acknowledgement protocol would be much more efficient. PCI makes too many compromises to the PC's architecture; we're just about ready for a new bus again. > Active high, edge triggered interrupts are an abomination (there > is no way to reliably share the interrupt line and you cannot even wire > or it). They are the reason why one never has enough interrupt lines on > ISA. I don't believe I ever suggested that this was the only alternative technique, and I'm certainly on record as not liking it either. -- \\ The mind's the standard \\ Mike Smith \\ of the man. \\ msmith@freebsd.org \\ -- Joseph Merrick \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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