[Bug 40024] Power management does not work on ATI Mobility Radeon 9700

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=40024

--- Comment #5 from Andrew Randrianasulu <randrik at mail.ru> 2011-11-02 04:00:35 UTC ---
Probably bad advice, but what if user  executes rovclock [1] on top of KMS ?

 [1] - http://www.thinkwiki.org/wiki/Rovclock - has some info about min. clocks
.... Also, not looked into modern KMS code yet, but people on #nouveau reported
their cards need proper memtimings, are we (radeon) setting them (on combios
and atombios cards ....)

There was another thread on Phoronix, with dynpm discussion, basically down to
"it will work if we start to re-clock memory early, before vblank period, so at
most few lines will be corrupted" but i can't find patches on dri-devel :(

http://phoronix.com/forums/showthread.php?57084-Gallium3D-Pipe-Video-To-Be-Merged-To-Mesa-Master&p=218105#post218105

ahlaht 

Date 07/12/2011
-----------------

"2. The engine clock and voltage can be changed freely without syncing to
vblank and so it should work fine with multiple monitors too. (This is very
cool.) There is no flickering provided CRTCs are kept ON while doing the
reclocking. (But there is probably some good reason why the code turns them OFF
by default.)

 3. The memory reclocking is much harder to do without flickering. Even if
synced perfectly to vblank the time runs out in the end and visible display
corruption occurs. The solution is to start the reclocking just few lines
BEFORE vblank. This way if there is any flickering it's limited to the last few
lines only.

 4. When idle and working properly dynpm doesn't use any more power than the
"low" profile, but it still responds immediately to any gpu load.

 I'm currently testing if these hacks are stable. I had some crashes when
writing them, but I think the problems should be fixed now..."

-----

I'm sure i saw patches ... but where?! kernel bugzilla?

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