Date: Wed, 5 Feb 1997 20:32:56 +0100 From: se@freebsd.org (Stefan Esser) To: msmith@atrad.adelaide.edu.au (Michael Smith) Cc: Brett_Glass@infoworld.com, se@freebsd.org, Andre.Albsmeier@mchp.siemens.de, freebsd-hardware@freebsd.org Subject: Re: 5 devices in 4 PCI Slots ? Message-ID: <19970205203256.YE44873@x14.mi.uni-koeln.de> In-Reply-To: <199702040003.KAA07826@genesis.atrad.adelaide.edu.au>; from Michael Smith on Feb 4, 1997 10:33:24 %2B1030 References: <9701038549.AA854983543@ccgate.infoworld.com> <199702040003.KAA07826@genesis.atrad.adelaide.edu.au>
next in thread | previous in thread | raw e-mail | index | archive | help
On Feb 4, msmith@atrad.adelaide.edu.au (Michael Smith) wrote: > Brett_Glass@infoworld.com stands accused of saying: > > Interesting. Is interrupt sharing implemented for other drivers as well > > (for instance, for PCMCIA multifunction cards that share an IRQ between an > > Ethernet NIC and a modem)? > > Interrupt sharing is a bus, not driver, issue. We've just done to death Well, it is a BUS + DRIVER issue, actually ... The BUS must physically support it (some kind of wired OR, or dedicated interrupt lines per slot fed into the PIC chip). The inputs must be level sensitive (it is possible to share edge triggered interrupts, but this does result in higher per interrupt overhead). And finally, the device driver must also support interrupt sharing. Its first action in the interrupt handler must be a test, whether THIS device was the cause of the interrupt, and an immediate return from the handler, if it was not ... Regards, STefan
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?19970205203256.YE44873>