RFC: Removal of some mutexes from the radeon driver

[Dave Airlie]

On Fri, May 11, 2012 at 11:10 AM, Christian König
<deathsimple at vodafone.de> wrote:
> 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.

The vram mutex is to block access to the VRAM during reclocking.

So if you reclocks a lot while running stuff you might notice.

Dave.