drm/i915: restore render clock gating on resume

Rather than restoring just a few clock gating registers on resume,
just reinitialize the whole thing.

Signed-off-by: Andy Lutomirski <luto@mit.edu>
[anholt: Fixed up for RC6 support landed since the patch was written]
Signed-off-by: Eric Anholt <eric@anholt.net>

1 files changed, 20 insertions, 15 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 902cc5386f19..279dc96e3eb2 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4584,28 +4584,33 @@ void intel_init_clock_gating(struct drm_device *dev)
                 struct drm_i915_gem_object *obj_priv;
                 int ret;
 
-                pwrctx = drm_gem_object_alloc(dev, 4096);
-                if (!pwrctx) {
-                        DRM_DEBUG("failed to alloc power context, RC6 disabled\n");
-                        goto out;
-                }
+                if (dev_priv->pwrctx) {
+                        obj_priv = dev_priv->pwrctx->driver_private;
+                } else {
+                        pwrctx = drm_gem_object_alloc(dev, 4096);
+                        if (!pwrctx) {
+                                DRM_DEBUG("failed to alloc power context, "
+                                          "RC6 disabled\n");
+                                goto out;
+                        }
 
-                ret = i915_gem_object_pin(pwrctx, 4096);
-                if (ret) {
-                        DRM_ERROR("failed to pin power context: %d\n", ret);
-                        drm_gem_object_unreference(pwrctx);
-                        goto out;
-                }
+                        ret = i915_gem_object_pin(pwrctx, 4096);
+                        if (ret) {
+                                DRM_ERROR("failed to pin power context: %d\n",
+                                          ret);
+                                drm_gem_object_unreference(pwrctx);
+                                goto out;
+                        }
 
-                i915_gem_object_set_to_gtt_domain(pwrctx, 1);
+                        i915_gem_object_set_to_gtt_domain(pwrctx, 1);
 
-                obj_priv = pwrctx->driver_private;
+                        dev_priv->pwrctx = pwrctx;
+                        obj_priv = pwrctx->driver_private;
+                }
 
                 I915_WRITE(PWRCTXA, obj_priv->gtt_offset | PWRCTX_EN);
                 I915_WRITE(MCHBAR_RENDER_STANDBY,
                            I915_READ(MCHBAR_RENDER_STANDBY) & ~RCX_SW_EXIT);
-
-                dev_priv->pwrctx = pwrctx;
         }
 
 out: