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Date:      Tue, 7 Apr 1998 09:36:52 -0400
From:      Randall Hopper <rhh@ct.picker.com>
To:        Donald Burr <dburr@POBoxes.com>, FreeBSD Questions <freebsd-questions@FreeBSD.ORG>
Cc:        FreeBSD Hardware <freebsd-hardware@FreeBSD.ORG>, multimedia@FreeBSD.ORG
Subject:   Re: BrookTree 848 causing my screen to get messed up, how to fix?
Message-ID:  <19980407093652.31657@ct.picker.com>
In-Reply-To: <XFMail.980406103905.dburr@POBoxes.com>; from Donald Burr on Mon, Apr 06, 1998 at 10:39:05AM -0700
References:  <XFMail.980406103905.dburr@POBoxes.com>

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Donald Burr:
 |I just acquired a BrookTree 848 based TV capture card.  It appears to be a
...
 |In any case, I got the driver compiled, and the fxtv port compiled and
 |working.  I can successfully view the TV tuner output in a window on my
 |screen.
 |
 |However, when that window is visible (i.e. not hidden behind any other
 |windows), it causes the rest of my screen to become garbled, so that
 |all windows (xterms, my Netscape browser, etc.) become virtually
 |unreadable.
 |
 |If the window is hidden behind another, nothing gets garbled.

Right.  If you run "fxtv -disableDirectV" or put "*disableDirectV: true" in
your Fxtv resource file or .Xdefaults, you'll not have this problem when
its on top either.  However that's the fall-back plan.  You'd prefer for
direct video to work if possible.

When the window is on top, fxtv configures the capture card to write
directly to your frame buffer directly rather than through X (very fast and
low overhead).  Works great as long as Fxtv can determine your frame buffer
memory aperature's geometry from the X server.

If you're running in a 24 or 32 bits-per-pixel video mode, here are some
things to try to get your direct video configured up correctly:

     fxtv -colorbars -xrm "Fxtv.Bpp24bit: 3"
     fxtv -colorbars -xrm "Fxtv.Bpp24bit: 4"
     fxtv -colorbars -xrm "Fxtv.Bpp32bit: 3"
     fxtv -colorbars -xrm "Fxtv.Bpp32bit: 4"

See if one of these doesn't get the TV all inside the window.  If you find
one that works, insert it into your Fxtv resource file or .Xdefaults.

However given that you have a 2Meg video card as you said, I suspect you're
probably running 16-bit in which case these don't help you.  If so, this is
an indication that the X server drivers for your card aren't returning the
correct frame buffer memory aperture geometry for it, and disabling direct
video is your best course of action for now.  Higher CPU utilization and
slower frame rates, but you won't get screen corruption.

I'll be happy to help you trace this down.  Let me know what you find out,
and send me the output of "fxtv -debug startup" and "xdpyinfo".  We can
determine if this is the X server's fault or not, and if so, you can flip
in a bug report to XFree.

 |The same thing happens when I use the Windows software that came with the
 |card.

Hmm.  Sounds like the Windoze Direct* drivers are confused about your frame
buffer geometry as well.

Randall Hopper


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