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From: Antony T Curtis <antony.t.curtis@ntlworld.com>
To: Palle Girgensohn <girgen@pingpong.net>
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Date: Thu, 15 Jul 2004 19:00:18 +0100
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cc: current@freebsd.org
Subject: Re: parallel port *slow*
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On Thu, 2004-07-15 at 16:42, Palle Girgensohn wrote:
> Hi!
> 
> 
> For a while now my parallel port (with printer hooked up) has been *really 
> SLOW*. Takes several minutes to print a single very simple page.
> 
> Any idea how to debug or what to try/fix?
> 
> All I see in the log is:

<snip>

> ppc0: <Parallel port> at port 0x378-0x37f irq 7 on isa0
> ppc0: SMC-like chipset (ECP/EPP/PS2/NIBBLE) in COMPATIBLE mode
> ppc0: FIFO with 16/16/16 bytes threshold

if you do a "man ppc" there are flags settable on the ppc device.
If you set the flags so that it is in ECP mode, it will be much faster.
Even EPP mode works faster. 

IIRC Compatible mode uses an interrupt for every character. EPP can
handle a burst of characters while ECP uses DMA so can transfer a large
block per interrupt.

-- 
Antony T Curtis <antony.t.curtis@ntlworld.com>