[Nouveau] Low power operational mode of nv50

[Martin Peres]

Le 22/01/2011 12:13, Jan Kiszka a écrit :
> Hi,
>
> what are the missing bits to get nv50-class hardware into lowest power
> mode? Even when clocking down to perflvl 0, the GPU temperature of my
> Quadro FX 880M is still quickly climbing until it reaches 60 °C and the
> fan goes on for a while (I tried up to 2.6.38-rc1 so far - any progress
> in nouveau-next?). This is not only annoying but also sucking several
> watts more than what is feasible - unfortunate for mobile operation.
>
> The benchmark is still the blob which runs the card at level 0 around 54
> °C, and that means fan-less. But as the blob is causing increasing
> troubles across suspend/resume, not to speak of all its other
> limitations. So I'd rather like to switch ASAP now.
>
> What may cause this different power consumption? As the clocking is
> apparently the same (the blob even claims to use a few more MHz), I was
> wondering if the less sophisticated firmware of nouveau could be the
> reason. Or is the host driver keeping the GPU too busy even in idle state?
>
> Is there anything I could do to help analyzing or even resolving this issue?
>
> Thanks,
> Jan
Hi,

To put it simply, I have no idea :s I spotted some strange behaviour 
(that could indicate some power management) when tracing the kernel but 
my attempts to mimic it led to ..... 0.1W less (I guess it's just noise).

I must admit I'm not working enough on it yet, this is because I would 
like to get safe recloking and fan management out of the door before 
looking at real power management, but if you have some knowledge in the 
field, I would love if you could give me a hand on this :)

I'm pretty sure the difference in power consumption is due to un-needed 
engines running. I may have a look at it this week as I'll be away from 
my desktop computer.

Anyway, I'll be in Germany next week, are you living close to Bochum? We 
could talk about this if you want/can.

Take care,
Martin