Minimal X Config File and Compiz

Kristian Høgsberg krh at
Wed Sep 13 19:49:54 UTC 2006

David Nielsen wrote:
>>> Did you solve the Firefox scrolling issue with compiz on an r300 based 
>>> card? Firefox becomes unusably slow over here (Radeon 9500pro) when I 
>>> switch to compiz but the effects themselves work smoothly.
>>> Regards,
>>>    Dennis
>> I see the same thing with the R100. Firefox scrolling is unbearable and
>> so is gnome-terminal scrolling, especially full screen.
> Admittedly that one is rather bad but it only happens if you scroll
> using the mouse wheel not if you grap the scrollbar - I'm thinking
> pango?

I know everybody likes to kick pango, but this is not pango's fault.  The 
problem is that when we run compiz on AIGLX, we kick out all pixmaps to host 
memory.  This means that XCopyArea (which is what drives most scrolling) is no 
longer accelerated and furthermore, for each line you scroll, we have to copy 
the pixmap contents back out to the card.  This is the big bottleneck in the 
compiz+AIGLX architecture, we're hoping to fix it post-fc6.


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