[Nouveau] Low power operational mode of nv50

[Martin Peres]

Le 22/01/2011 13:38, Jan Kiszka a écrit :
> [please keep me on CC]
ok, sorry about that.
> On 2011-01-22 12:49, Martin Peres wrote:
>>
>> 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).
> Yeah, I think we are looking something like 3-5 Watt.
Yes
>> 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,
> I agree that being able to safely switch between power modes is
> important. But, at least for the rather common mobile scenarios, it is
> first of all important to have acceptable 2D support (I think that's
> already the case) which does not suck your battery and steal your nerves
> via noisy fans. And that's still preventing me to switch.
Well, I was more pragmatic: "Let's do what we already 'know' we can do".
Also, I wouldn't know what are the normal instructions if I hadn't 
implemented
the reclocking support myself.

I understand your frustration though.
>> but if you have some knowledge in the
>> field, I would love if you could give me a hand on this :)
> Yet I do not know much about the nouveau or the hardware it drives. But
> I'm not really unfamiliar with messing around in drivers and kernels. So
> if you tell me what might be worth looking at or trying out...
Cool, well, what you can do is look at mmiotraces (I can provide you 
with some or you could make one yourself: 
http://nouveau.freedesktop.org/wiki/MmioTrace )

Send me your vbios and the trace when you're done. I'll tell you what to 
look for and what is already known :)

You'll also need to read 
https://github.com/pathscale/pscnv/wiki/Power-Management and 
https://github.com/pathscale/pscnv/wiki/Introductorycourse .

Then, you'll need the demmio tool to easily read the mmiotrace 
(https://github.com/pathscale/pscnv/wiki/RE_Tools).

$ demmio my_mmio_trace.txt | less -R

Then you need to look at the right place, I would suggest going to the 
position where the reclock is happenning (type "/0x4020 <=", less will 
search for "0x4020 <=" in the text).

I'll tell you more when I receive your mail (send it to mmio dot dumps 
at gmail dot com, my mailbox is already almost full of vbios).
>> Anyway, I'll be in Germany next week, are you living close to Bochum? We
>> could talk about this if you want/can.
> Not really close: Munich. Guess we have to stick with email or chat. :)
Indeed :)

Martin