kern/78711: Parallel printer incredibly slow

[Jason Bacon]

Almost forgot...  Thanks!

On Sat, 12 Mar 2005, Bruce Evans wrote:

> 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
>