Intel i915 freeze on latest git

[Francesco Allertsen <fallertsen@gmail.com>]

Hi Chris and all,

I have tried the latest git (-rc3) and I get a complete freeze when X
starts.

I've bisected it and the first bad commit is this:

commit d5bb081b027b520f9e59b4fb8faea83a136ec15e
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Wed Jan 5 12:01:26 2011 -0800

    drm/i915: cleanup rc6 code
    
    Cleanup several aspects of the rc6 code:
      - misnamed intel_disable_clock_gating function (was only about rc6)
      - remove commented call to intel_disable_clock_gating
      - rc6 enabling code belongs in its own function (allows us to move the
        actual clock gating enable call back into restore_state)
      - allocate power & render contexts up front, only free on unload
        (avoids ugly lazy init at rc6 enable time)
    
    Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
    [ickle: checkpatch cleanup]
    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

I've tried to revert it on top of -rc3 and everything works great.

I don't know which part of the code is wrong, could you please check it?
If you need more information just ask.

Thanks.

Bye
Francesco