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Date: Wed, 12 Feb 1997 08:06:51 -0700 (MST)
Message-Id: <199702121506.IAA08268@xeno.xinside.com>
From: Thomas Roell <roell@crab.xinside.com>
To: Amancio Hasty <hasty@rah.star-gate.com>
Cc: Randall Hopper <rhh@ct.picker.com>, multimedia@freebsd.org
Subject: Re: Bt848 driver & Wincast -- some success 
In-Reply-To: <199702120504.VAA26988@rah.star-gate.com>
References: <19970211232548.58351@ct.picker.com>
	<199702120504.VAA26988@rah.star-gate.com>
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In your message of 11 February 1997 you write:

> Hi,
> 
> You need the B848 Databook from Brooktree if you want to hack on the
> driver, period.
> 
> What is your CPU and motherboard chipset, example Natoma or Triton...
> 
> If you have a Mercury chipset, then you don't have enough PCI bandwith 
> to drive a 640x480 32bits picture. Also try playing with the PCI parameters
> in your BIOS. Your PCI clock rate should be around 32 or so and not 60 or
> higher.
> 
> You can try 320x240 with something like 15bits or 8bits color depth.
> 
> The ghostimage that you are experiencing in your system is an indication
> that your PCI chipset is not able to keep up with the Bt848.
> 
> The driver does not have the ioctls to transfer video to memory and
> is not hard to add . I can provide this feature before the end of 
> the week;however, if you want to take advantage of this feature
> then you will have to ask the XFree86 team or peruse thru their 
> release notes for an appropiate video card which supports linear
> frame buffering.

*smile* Or Xi Graphics (the artist formerly known as ...)

Actually writing YUV422 and 320x240 makes more sence that 15bpp or
8bpp TrueColor. The graphics chip can do the color-space conversion.

What I'm really curious about is whether the Bt848 can do
doublebuffering. I mean an even field into buffer A and an odd field
into buffer B.

- Thomas
-- 
             Thomas Roell   /\       Ein Nasshorn und ein Trockenhorn
             Xi Graphics   /  \/\ _    spazierten durch die Wueste,
      roell@xinside.com   /   /  \ \    da stolperte das Trockenhorn,
                         / Brumpft! \    und's Nasshorn sagte: "Siehste!"