[PATCH v2] drm/i915: fix long-standing SNB regression in power consumption after resume

[Jesse Barnes]

On Wed, 17 Jul 2013 10:22:58 +0400
Konstantin Khlebnikov <khlebnikov at openvz.org> wrote:

> This patch fixes regression in power consumtion of sandy bridge gpu, which
> exists since v3.6 Sometimes after resuming from s2ram gpu starts thinking that
> it's extremely busy. After that it never reaches rc6 state.
> 
> Bug exists since kernel v3.6, commit b4ae3f22d238617ca11610b29fde16cf8c0bc6e0
> ("drm/i915: load boot context at driver init time").
> 
> For some reason RC6 is already enabled at the beginning of resuming process.
> Following initliaztion breaks some internal state and confuses RPS engine.
> This patch disables RC6 at the beginnig of resume and initialization.
> 
> I've rearranged initialization sequence, because intel_disable_gt_powersave()
> needs initialized force_wake_get/put and some locks from the dev_priv.
> 
> References: https://bugs.freedesktop.org/show_bug.cgi?id=54089
> References: https://bugzilla.kernel.org/show_bug.cgi?id=58971
> Signed-off-by: Konstantin Khlebnikov <khlebnikov at openvz.org>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Jesse Barnes <jbarnes at virtuousgeek.org>
> ---

My hero!

So the later init change didn't work?

Either way, great to have this fix in the tree... thanks again.

-- 
Jesse Barnes, Intel Open Source Technology Center