[Savage40] Long-Standing Bug

[Alex Deucher]

--- Tim Roberts <timr at probo.com> wrote:

> For those of you who are still able to apply active resources to the 
> Savage driver, there is one outstanding bug that has caused much
> concern 
> that shouldn't be terribly difficult to chase down.
> 
> The problem happens when you try to display a gradient background
> with a 
> window manager.  When you do so, you see obvious striping in the
> colors 
> -- striping that you should not see at depth 24.  It looks as bad or 
> worse than depth 16.
> 
> This bug seems to have been introduced in the 1.21t timeframe, at the
> 
> same time I added support for the xgamma extension.  When I did that,
> I 
> also increased the "number of DAC bits per component" from 6 to 8.  I
> 
> _suspect_ the striping bug is related to that change.  Someone, 
> somewhere, is still confused about the DAC depth, and is masking off
> 2 
> bits that it shouldn't.
> 
> Volunteers?

I looked into this a little this weekend, but I didn't have much luck. 
It looks like the savages only have a 6 bit DAC, but I don't really see
anything else that looks too out of place.  I did notice that lots of
other drivers set a mem RAC for colormap setup, I don't know if the
savages needs one too or not.  I've never really messed with the
xf86colormap* stuff, so any pointers would be welcome.  Tim, do you
have a old copy of savage_driver.c prior to the break?  I'd be curious
to check it out.

Alex
 



		
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