[Nouveau] "enable ctxprog xfer only when we need it to save power" introduces big performance regression

[Martin Peres]

Hi Marcin,

As promised, I started working on your performance problem.

Le 29/12/2011 02:38, Marcin Slusarz a écrit :
> I tried to implement xfers runtime switching, but couldn't figure out 
> how to change ctxprog behaviour without rebuilding and reuploading 
> whole thing. Reading host-writable memory from ctxprog would be enough. 
Well, I did that for you (see the patch enclosed). The patch uses the 
4th ctxprog flag register's bit 0 to store the wanted behaviour.
Mwk suggested me to do so and it worked perfectly.

You have all the instructions in the commit message, please report on 
the actual results!

By the mean time, I'll plug it to a PM brain so as it would switch back 
and forth between the two modes according to the load or the perflvl.

Take care,

Martin