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Date: Fri, 27 Dec 1996 11:30:01 -0800 (PST)
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From: Bruce Evans <bde@zeta.org.au>
Subject: Re: kern/2270: Hayes ESP serial card locks system as of 12/01 ke
Reply-To: Bruce Evans <bde@zeta.org.au>
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The following reply was made to PR kern/2270; it has been noted by GNATS.

From: Bruce Evans <bde@zeta.org.au>
To: bde@zeta.org.au, george@cia-g.com
Cc: freebsd-gnats-submit@freebsd.org
Subject: Re: kern/2270: Hayes ESP serial card locks system as of 12/01 ke
Date: Sat, 28 Dec 1996 06:16:42 +1100

 >I stepped through the sio.c versions from 11/30/1996.  1.152 works,
 >1.153 doesn't.  The diff between the these two versions looks simple
 >enough.  The logs says "Reset h/w fifos (if any) in siostop(). ...".
 >What does this mean with respect to the Hayes ESP?  Is there a
 >different way to do this for the ESP?
 
 Good work.
 
 Look at the magic outb for the ESP case near line 902.  This sets the
 FIFO_RCV_RST and FIFO_XMT_RST bits in combination with the FIFO_DMA_MODE
 bit.  I don't know what this does (I don't have any documentation about
 the ESP).  The author of the ESP changes said that the DMA bit doesn't
 have anything to do with DMA.  Apparently the reset bits aren't for reset
 either.
 
 Bruce