kern/78711: Parallel printer incredibly slow

[Bruce Evans]

The following reply was made to PR kern/78711; it has been noted by GNATS.

From: Bruce Evans <bde at zeta.org.au>
To: Suporte Matik <asstec at matik.com.br>
Cc: freebsd-bugs at freebsd.org,
	Jason Bacon <bacon at smithers.neuro.mcw.edu>,
	FreeBSD-gnats-submit at freebsd.org
Subject: Re: kern/78711: Parallel printer incredibly slow
Date: Sat, 12 Mar 2005 13:11:09 +1100 (EST)

 On Fri, 11 Mar 2005, Suporte Matik wrote:
 
 > On Friday 11 March 2005 19:42, Jason Bacon wrote:
 >>> Description:
 >>
 >> 	The parallel printer runs ridiculously slow.  It prints normally
 >> 	for about 30 seconds, then prints one line every 5 or 10 minutes.
 >>...
 >
 > any two lines text file needs 15 minutes to be printed
 >
 >>> Fix:
 >>
 >> 	lptcontrol -s resolves the problem.  This looks to me much
 >>...
 >
 > does not fix, the problem is as well with lpr and cups local/remote
 >
 > the only way to get "some more speed" is using b/w and 150 dpi on a HPDJ, any
 > gray or color mode is slow
 
 Try changing the interrupt storm threshold (hw.intr_storm_threshold) to
 something larger than the printer can generate.  FreeBSD-5.3 has interrupt
 storm detection that misdetects the very high interrupt rates that can
 be caused by printers (combined with low quality interrupt handling in
 the lpt driver) as interrupt storms.
 
 > doesn't matter what you set in the BIOS or whatever, any gray or colormode on
 > 5.3 is that inacceptable slow
 >
 > using the exactly same printer and port settings on 5.2.1 or 4.11 brings you
 > back to the expected printing speed
 
 FreeBSD-5.2 and FreeBSD-current have different bugs in interrupt storm
 detection and handling.  In at least some versions, the bugs make printers
 go even slower if an interrupt storm is misdetected for them, but
 misdetection is apparently rarer.
 
 FreeBSD-4 doesn't have interrupt storm detection, so any problems with
 printer speed are local to the driver.
 
 Bruce