RFC: Removal of some mutexes from the radeon driver

["Christian König" <deathsimple@vodafone.de>]

Hi everybody,

well the following patches remove the cs and vram mutex from the radeon driver
and so are something very experimental. The first three just move what I know
to be still critical into the protection of the ring mutex, and the other two
actually remove the mutexs.

Interestingly it still survives a couple of hours running the following script:

while true
do
        for (( x = 10, y = 45, i = 0; $i < 144; i = $i + 1 ))
        do
                glxgears -geometry 100x100+$x+$y > /dev/null 2>&1 &
                x=$(expr $x + 120)
                if [ $x -gt 1920 ]
                then
                        x=10
                        y=$(expr $y + 110)
                fi
        done

        sleep 30

        killall glxgears
done

So the mutexes doesn't seem to protected something so critical and I'm
wondering why we still have them so widely locked.

Cheers,
Christian.

PS: I'm away for the next week or so don't expect any response soon.