[Bug 28456] radeon dri detects different number of pipes each boot

https://bugs.freedesktop.org/show_bug.cgi?id=28456

--- Comment #6 from Alexandre alexandre.nunes@gmail.com 2010-09-14 08:36:10 PDT --- It still happens on at least linux 2.6.35.4 (vanilla).

One thing I realized is that once drm only sees 1 quad pipe, the irq rate from the card seems to increase dramatically. I couldn't take the time to take measurements, but it seems to go from about < 100 per second w/ 3 pipes actives, to something like 300 ~ 900 per second.

Perhaps this "storming" is causing the slowdown I'm seeing?