From 81e7f2002b7db269799ebdac0d905574c0a85d1d Mon Sep 17 00:00:00 2001
From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Fri, 15 Aug 2014 01:21:55 +0300
Subject: [PATCH] drm/i915: Idle unused rings on gen2/3 during init/resume
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gen2/3 platforms have a boatload of rings we're not using. On my 830
the BIOS/hw can leave some of those "active" after resume which will
prevent c3 entry. The ring is apparently considered active whenever
head != tail even if the ring is disabled.

Disable and clear all such unused ringbuffers on init/resume.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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