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Date:      Wed, 26 Mar 1997 11:02:13 -0800
From:      Amancio Hasty <hasty@rah.star-gate.com>
To:        Michael Petry <petry@netwolf.NetMasters.com>
Cc:        multimedia@freebsd.org
Subject:   Re: Bt848 enhancements for this week 
Message-ID:  <199703261902.LAA05311@rah.star-gate.com>
In-Reply-To: Your message of "Wed, 26 Mar 1997 07:37:54 EST." <199703261237.HAA02315@netwolf.NetMasters.com> 

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Hi Michael,

The issue is very simple. The dma controller can swap bytes or words on the 
fly.

Memory mapped register 0xd8 or bktr_color_ctl:

bit 3 word swap odd
bit 2 word swap even
bit 1 byte swap odd
bit 0 byte swap even

For apps which write directly to the vga's linear frame buffer you want
to be able to set the correct pixel order for the card. And for apps
which don't write directly to the frame buffer you can save  byte
swapping in the X server by presenting a matching pixel order to
the X server.


We need a way to modify IOCTL_GEO_RGB16 and IOCTL_GEO_RGB24 to pass along
the pixel order. Then in build_dma_prog set the appropiate
bits for bktr_color_ctl based upon capturing even, odd  , or even and odd
frame, and the color depth 16 bits vs 32bits.

	Enjoy,
	Amancio


>From The Desk Of Michael Petry :
> 
> Shhhh, Please don't tell my Matrox Millenium that is shouldn't be working.  
> Watching TV while hacking makes me feel like I moved up a notch in the Couch 
> Potato evolutionary chain. (Who's working on the PCI card the provides 
> exercise)
> 
> Showing my ignorance.  What's the core issue? I can only guess that the 
> dynamics of the controls have allow me to compensate for the switch of byte 
> swapping of BXR to RXB. Is it just that the hue and croma controls work 
> backwards?  I've been using the Xfree86 beta driver and running in 32 bit mod
e.
> 
> >1. Provide functionality to support cards such as the Matrox Millenium , 
> >   Mystique which have a different pixel order BGR as opposed to RGB which
> >   most of us probably have.
> 
> 





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