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To: Amancio Hasty <hasty@rah.star-gate.com>
cc: Steve Passe <smp@csn.net>, multimedia@freebsd.org
From: "Louis A. Mamakos" <louie@TransSys.COM>
Subject: Re: Anyone on the list who can check-in the bt848 driver? 
References: <199703100033.QAA00370@rah.star-gate.com> 
In-reply-to: Your message of "Sun, 09 Mar 1997 16:33:39 PST."
             <199703100033.QAA00370@rah.star-gate.com> 
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Date: Sun, 09 Mar 1997 22:22:17 -0500
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I might be all wet here, but I think that the kernel only calls the
driver's close routine when the *last* reference to the open device
is closed.  It's been awhile since I've hacked device driver code, but
I think this was the case a while ago.

This may be a good reason to use a seperate (minor) device to control
the tuner, or roll that function into the same application.

Now, for something completely different - speaking of API design...

A couple of years ago, I wrote a bunch of code on NeXTSTEP boxes.  If you
happened to have a NeXTDimension board for your Cube, you got a nify
piece of hardware which did much of what do with the Bt848 hardware, plus
generating NTSC video goesouta for a portion of the display screen.  Anyway,
they had an interested UI class, called NXLiveVideo, which was a subclass
of the "normal" Window class (more or less).  It did the obvious sorts of
things, and the Display PostScript server did the "right thing" to make
clipping, and whatnot work correctly.  So, the application had a minimum
of changes to get video into the window (which you could also do some
normal operations inside, too).  Based on this experience, the thing that
feels the most "right" is to get support in the X server for this type
of hardware and capability.  I hope that someone who knows much more than
I about the guts of the X server might ponder this for it's applicability
to the problem at hand.

louie