Date: Mon, 19 Feb 2001 09:36:54 +0000 From: Antony T Curtis <antony@abacus.co.uk> To: Andreas Klemm <andreas@FreeBSD.ORG> Cc: freebsd-stable@FreeBSD.ORG Subject: Re: stray irq's 7, printing hangs, about 20000-50000 irqs per second ... Message-ID: <3A90E936.BD86EA65@abacus.co.uk> References: <20010217185425.A450@titan.klemm.gtn.com>
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Andreas Klemm wrote: > > Somethings wrong with the parallel printing device. > > All print jobs hang no matter if I'm using polled or IRQ driven > mode (using lptcontrol). > > With a FreeBSD of today I get stray IRQ's 7 and when looking at the > IRQs I notice 20000-50000 (!!!) per second on a print job ... Having that volume of IRQs for the printer port is normal for standard mode printer port. There is one IRQ signal for each and every byte sent. You may want to investigate changing the default mode of the printer port driver by playing with the flags for the printer port device ( see `man ppc' ) ECP mode should give the best performance by using a DMA channel to transfer data and only issuing an IRQ at the end of DMA. Should yield up to 2MB/s. However, I always seem to get occasional bytes going missing when printing to a Panasonic laser printer. Otherwise, one can opt for EPP or PS/2 mode, which should enable the small FIFO available in most printer ports - this should slash the number of IRQs. -- ANTONY T CURTIS Tel: +44 (1635) 36222 Abacus Polar Holdings Ltd Fax: +44 (1635) 38670 > The trouble with superheros is what to do between phone booths. > -- Ken Kesey To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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