Re: [PARPORT] EPP speed results on ppdev

Tim Waugh (
Fri, 26 Nov 1999 13:21:47 +0000 (GMT)

On Mon, 22 Nov 1999, chris wrote:

> I have built the 2.3.28 development kernel and have used it to
> perform EPP data read transfer through the parallel port at data rates
> around 340Kbytes/sec, which I believe is still a little slower than it
> should be. In addition there seems to be some data dropouts.

Can you show me the application code you're using?

> After looking at the timing on a logic analyzer I noticed that
> between reading in a bytes there is about a 3microsecond delay period
> before the parallel port is ready to read in another byte. Is clearing
> the timeout bit before each data read cycle a necissity?

Which function is being used: parport_pc_epp_read_data or
parport_ieee1284_epp_read_data? (dmesg output will say whether it's using
hardware or not)

> What about block transfers has anybody tried that with the ppdev
> driver in EPP mode?

I guess you haven't, which might be the cause of the delay. Comparative
timings would be good..


-- To unsubscribe, send mail to: --
-- with the single word "unsubscribe" in the body of the message. --

This archive was generated by hypermail 2.0b3 on Fri 26 Nov 1999 - 08:24:16 EST