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