Return to BSD News archive
Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!news.mira.net.au!news.mel.connect.com.au!munnari.OZ.AU!news.ecn.uoknor.edu!news.eng.convex.com!newshost.convex.com!bcm.tmc.edu!pendragon!news.msfc.nasa.gov!newsfeed.internetmci.com!news.mathworks.com!fu-berlin.de!cs.tu-berlin.de!uni-erlangen.de!news.tu-chemnitz.de!irz401!orion.sax.de!uriah.heep!news From: j@uriah.heep.sax.de (J Wunsch) Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: slow print problem Date: 27 Jun 1996 20:42:08 GMT Organization: Private BSD site, Dresden Lines: 29 Message-ID: <4qurn0$9p@uriah.heep.sax.de> References: <31C98DE4.41C67EA6@rockwell.cz> <31C9C2C3.675102B3@lambert.org> <4qrnhl$bc@anorak.coverform.lan> Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) NNTP-Posting-Host: localhost.heep.sax.de Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Newsreader: knews 0.9.6 X-Phone: +49-351-2012 669 X-PGP-Fingerprint: DC 47 E6 E4 FF A6 E9 8F 93 21 E0 7D F9 12 D6 4E brian@awfulhak.demon.co.uk (Brian Somers) wrote: > : Your printer port is on IRQ 7, which is the "garbage" interrupt > : for all unrecognized interrupts, ... > What's a "garbage" interrupt ? Though Terry's explanation was not 100% water-proof, there once has been a good explanation for the "garbage interrupt" by Rod Grimes. Basically, it's a (documented) behaviour of the original i8259 PIC (programmable interrupt controller) where it raises an interrupt request at the lowest IRQ level (highest number -- 7 for the master PIC, 15 for the slave PIC) when there has been an actual interrupt request on an input line that disappeared again before it could be prioritized. This is usually a (benign) indication of poor hardware generating spikes on an IRQ line under some circumstances. Several ISA boards are known to have caused this (IDE controllers, UARTs, FDCs). Unless you've got an lpt driver that operates on irq 7, this is also known as the "Stray IRQ 7" problem (sometimes also IRQ 15, but much rarer). -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)