[PATCH 0/9] drm/radeon/kms: update pm code

[Alex Deucher]

On Sat, May 8, 2010 at 7:14 AM, Klaus Doblmann B.A.
<klaus.doblmann at gmail.com> wrote:
> On Fri,  7 May 2010 17:16:11 -0400
> Alex Deucher <alexdeucher at gmail.com> wrote:
>
>> This set of patches applies on top of the code in drm-radeon-testing.
>>
>> I've been testing this code pretty hard this week and it's been solid.
>> In addition to some fixes on top of what's in d-r-t, it also reworks
>> the pm code to support two basic methods:
>>
>> 1. "dynpm"
>> 2. "profile"
>>
>> You can select the methods via sysfs.  Echo "dynpm" or "profile" to
>> /sys/class/drm/card-0/device/power_method.
>>
>> The "dynpm" method dynamically changes the clocks based on the number of pending
>> fences, so performance is ramped up when running GPU intensive apps, and
>> ramped down when the GPU is idle.  The reclocking is attemped during
>> vertical blanking periods, but due to the timing of the reclocking
>> functions, doesn't not always complete in the blanking period, which can
>> lead to flicker in the display.  Due to this, dynpm only works when a single
>> head is active.
>
> Hi Alex,
>
> I just built a new version of d-r-t with your patches from yesterday
> applied on top and wanted to share my experience with you and the list
> (Radeon 2600XT mobile):
>
> Dynpm has gotten unusable for me as there's a noticeable effect on
> mouse movement (getting sluggish)
>
>>
>> The "profile" method exposes 4 profiles that can be selected from:
>> 1. "default"
>> 2. "auto"
>> 3. "low"
>> 4. "high"
>> Select the profile by echoing the selected profile to
>> /sys/class/drm/card-0/device/power_profile.
>>
>
> the profile setting works but I can't check which clock speeds are
> set as I don't get any feedback (dmesg) anymore (Someone have any
> input on this?). The temps are unaffected whether I use the low or high
> profile, the only way I can tell that some things are working is by a
> 2000 fps-difference when running glxgears (something like 4000 on low
> and 6000 on high). I also attached a wattmeter to my my machine and the
> wattage alternates but I think I'm getting something along the lines of
> a 10W decrease in power consumption - it's very hard to tell, though.
> dynpm is a bit more effective and I even get lower temps (just under
> 50° compared to over 53 with the profile settings) but it's unusable
> right now as I already mentioned.
>
> All in all very nice work so far (this goes for all of you who've
> worked on radeon KMS PM!) - with the latest set of patches this is the
> first "revision" of KMS PM that actually "works" on my machine :)
>

Thanks for testing; we are definitely planning on further
improvements, this is just a step on the way.   The power drops
further when your monitors go off so that will save additional power
when your machine is idle.  If you want to see the state transitions,
revert this patch:
http://people.freedesktop.org/~agd5f/pm-drt/0009-drm-radeon-kms-pm-make-pm-spam-debug-only.patch
However, it will spam your kernel log.

Alex

> Klaus
>
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