i915: reprogram power monitoring registers on resume

Fixes issue where i915_gfx_val was reporting values several
orders of magnitude higher than physically possible (without
leaving scorch marks on my thighs at least.)
Signed-off-by: NKyle McMartin <kyle@redhat.com>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Cc: stable@kernel.org
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_suspend.c

@@ -862,8 +862,10 @@ int i915_restore_state(struct drm_device *dev)
 	/* Clock gating state */
 	intel_init_clock_gating(dev);
 
-	if (HAS_PCH_SPLIT(dev))
+	if (HAS_PCH_SPLIT(dev)) {
 		ironlake_enable_drps(dev);
+		intel_init_emon(dev);
+	}
 
 	/* Cache mode state */
 	I915_WRITE (CACHE_MODE_0, dev_priv->saveCACHE_MODE_0 | 0xffff0000);

drivers/gpu/drm/i915/intel_drv.h

@@ -296,6 +296,7 @@ extern void intel_crtc_fb_gamma_get(struct drm_crtc *crtc, u16 *red, u16 *green,
 extern void intel_init_clock_gating(struct drm_device *dev);
 extern void ironlake_enable_drps(struct drm_device *dev);
 extern void ironlake_disable_drps(struct drm_device *dev);
+extern void intel_init_emon(struct drm_device *dev);
 
 extern int intel_pin_and_fence_fb_obj(struct drm_device *dev,
 				      struct drm_gem_object *obj,