Re: VERY slow scrolling on radeon graphics card: debugging atiming issue?

From: Pavel Machek
Date: Sun Jan 02 2011 - 04:00:10 EST


Hi!

> The thing is: that same scrolling becomes much faster
> when I "do something" else while it scrolls up. First
> I noticed this when I wanted to switch to another vt
> while it were scrolling -- I held down Ctrl key on my
> keyboard, and out of the sudden the scroll speed up
> dramatically.
>
> It turned out I can speed the thing to about 10 times
> by generating some load: hit and hold a key on the
> keyboard (generates interrupts?), run kernel compile
> in the background (generates disk interrupts?), move
> mouse...

Try "irqpoll"?

Will cpu load speed it up, too? (Like yes > /dev/null)?

> Any hints on where to go from there are apprecated.
>
> The hardware is an AMD780g-based motherboard with
> and Athlon CPU, I've seen the same behavour from
> many other similar boards. Kernels - all up to
> the current 2.6.36.2, sine the old days when kms
> for radeon first appeared in staging.

Watch /proc/interrupts to see if radeon uses them and if they appear
to work?
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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