The docs are not very clear on exactly what this means. Another doc
however mentioned that [not] enabling this can significantly increase
consumption impact.
Some early tests show no perf regression in Nexuiz, but a fairly
significant regression in OA (252FPS -> 240FPS).
Unfortunately I do not have a good setup to check if it actually helps
with power.
CC: Daniel Vetter <daniel.vetter at ffwll.ch>
Signed-off-by: Ben Widawsky <benjamin.widawsky at intel.com>
---
drivers/gpu/drm/i915/i915_dma.c | 5 +++++
drivers/gpu/drm/i915/i915_reg.h | 3 +++
2 files changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 333b746..7358be8 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1218,6 +1218,11 @@ static int i915_load_gem_init(struct drm_device *dev)
drm_mm_init(&dev_priv->mm.stolen, 0, prealloc_size);
mutex_lock(&dev->struct_mutex);
+
+ if (i915_powersave && IS_IVYBRIDGE(dev))
+ I915_WRITE(GEN7_MISCCPCTL,
+ I915_READ(GEN7_MISCCPCTL) | GEN7_DOP_CLOCK_GATE_ENABLE);
+
if (intel_enable_ppgtt(dev) && HAS_ALIASING_PPGTT(dev)) {
/* PPGTT pdes are stolen from global gtt ptes, so shrink the
* aperture accordingly when using aliasing ppgtt. */
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 972321f..db0b480 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3991,6 +3991,9 @@
#define GEN6_RC6 3
#define GEN6_RC7 4
+#define GEN7_MISCCPCTL 0x9424
+#define GEN7_DOP_CLOCK_GATE_ENABLE (1<<0)
+
#define G4X_AUD_VID_DID 0x62020
#define INTEL_AUDIO_DEVCL 0x808629FB
#define INTEL_AUDIO_DEVBLC 0x80862801
--
1.7.10
