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SGI VW 540, fbdev and pot pourii of faults and evidence..:-)

To: linux-fbdev@vuser.vu.union.edu
Subject: SGI VW 540, fbdev and pot pourii of faults and evidence..:-)
From: phil <philloc@janus.lsd.ornl.gov>
Date: Sat, 5 Aug 2000 19:13:15 -0400 (EDT)
Cc: linux@cthulhu.engr.sgi.com
Reply-to: i15@ornl.gov
Sender: owner-linux-mips@oss.sgi.com
        Hi Folks,

I have presented below a small list of "features" with the SGI kernel
driver for fbdev (no particular order) , and would like to know if any of
the symptoms, indicate general frame buffer problems, or specific hardware
implementation issues.

I would also like to ask, if SGI is likely to make the hardware specs OSS
(for cobalt etc.), so that those with the skill (this is not my forte, but
I will try...), can stabilise this otherwise competent port.

1. After boot , no matter what video mode one is in, the text console is
zippy. After using X (or changing modes using fbset) the text scrolling is
*painfully* slow. There is no apparent difference in the kernel mechanism
when switching, so is it just the boot state that works?



2.In X(4.01)  all video modes (800x600,1024x768,1280x1024,1600x1200) work
in 8 bit and 16 bit colour.

In Depth 24 (-fbbpp 32) , 1280x1024 is stable, but tinted green.

In Depth 24 (-fbbpp 32) , 1600x1200 is "shivering, left-right", and
tinted green.


        Empirical observations (i.e. writing known patterns to the
/dev/fb0 device) indicate that SGI reverse RGB for 888 format, compared to
RGB565. That is red offset=0, green=8,blue=16 rather than red=24 etc.. I
have reversed the assignment in the "var" structure (in sgivwfb_set_var )
and in setcolreg the offsets are used, but to no effect. What else needs
changing?


        Kind Regards

        PHiL


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