Date: Thu, 01 May 1997 16:06:28 -0700 From: Amancio Hasty <hasty@rah.star-gate.com> To: Randall Hopper <rhh@ct.picker.com> Cc: Doug White <dwhite@resnet.uoregon.edu>, multimedia@freebsd.org Subject: Re: Updated driver (bt848-970424) Message-ID: <199705012306.QAA00449@rah.star-gate.com> In-Reply-To: Your message of "Thu, 01 May 1997 07:05:21 EDT." <19970501070521.63393@ct.picker.com>
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>From The Desk Of Randall Hopper : > > Ahhh, I think I know what's going on now. The Bt's 4Bpp format w/ no byte > swapping is: ARGB. With byte swapping, you get access to BGRA, GBAR, and > RABG. According to your visual's RGB masks (RGB: 0000FF,00FF00,FF0000) and > display frame buffer depth (4Bpp), seems you need an ABGR ordering. The Bt > can't do it, thus the drop-back to X images. Sorry about that. > > If the Mach64 server support changing the pixel component ordering for that > 4Bpp/24bpp mode to ARGB (I know the chip supports it at least), that should > get you going there. Otherwise 15/16bpp might be your best option. > > Randall Also, if the X server supports 24bit then the Bt848 can do BGR and drop the "A". This can be done by setting the PCI Enable Bytes on the Write Risc Instructions . PCI Enable Bytes is field 15:12 . In this case set the Bt848 to output 32bit , word swap, byte swap, and set bit 12. I don't think that Mach64 supports 24bit. Nevertheless, we should plan to incorporate the PCI Enable Bytes feature. Enjoy, Amancio
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