[Intel-gfx] [PATCH] drm/i915: Don't update the render-clock for every bo.

[Chris Wilson]

Only update the render-clock on transition from busy to idle and vice
versa, or else we burn a significant percentage of the cpu just rewriting
the register -- not quite as power-friendly as intended ;-)

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Jesse Barnes <jbarnes at virtuousgeek.org>
---
 drivers/gpu/drm/i915/intel_display.c |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 33113c7..1ec3bd3 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4003,8 +4003,13 @@ void intel_mark_busy(struct drm_device *dev, struct drm_gem_object *obj)
 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
 		return;
 
-	dev_priv->busy = true;
-	intel_increase_renderclock(dev, true);
+	if (!dev_priv->busy) {
+		dev_priv->busy = true;
+		intel_increase_renderclock(dev, true);
+	} else {
+		mod_timer(&dev_priv->idle_timer, jiffies +
+			  msecs_to_jiffies(GPU_IDLE_TIMEOUT));
+	}
 
 	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
 		if (!crtc->fb)
-- 
1.6.5.3