[Intel-gfx] [PATCH] drm/i915: Decrease pll->refcount when freeze gpu

[Xiong Zhang]

display.crtc_mode_set will increase pll->refcount, but no one will
decrease pll->refcount when freeze gpu. So when gpu resume from freeze,
pll->refcount is still larger than zero. This is abnormal

Without this patch, connecting vga screen on Haswell platform, there
are following results:
1. when resume S3, call trace exist in intel_ddi_put_crtc_pll()
2. when resume s4, vga monitor is black. because intel_ddi_pll_mode_set()
   return false and haswell_crtc_mode_set() exit without setting mode

With this patch, I don't find S3 and S4 regression on SandyBridge
and IvyBridge platform connecting VGA, HDMI and DP screen.

Signed-off-by: Xiong Zhang <xiong.y.zhang at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 0485f43..0065735 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -575,8 +575,10 @@ static int i915_drm_freeze(struct drm_device *dev)
 		 * Disable CRTCs directly since we want to preserve sw state
 		 * for _thaw.
 		 */
-		list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
+		list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
 			dev_priv->display.crtc_disable(crtc);
+			dev_priv->display.off(crtc);
+		}
 
 		intel_modeset_suspend_hw(dev);
 	}
-- 
1.7.9.5