diff --git a/drivers/gpu/drm/nouveau/nv50_display.c b/drivers/gpu/drm/nouveau/nv50_display.c
index 7ba28e08ee3198de2094c12e1c2376f53c7934f4..ce440e2e58ca8e2a8ed698d2dd5c3f5968ac16a4 100644
--- a/drivers/gpu/drm/nouveau/nv50_display.c
+++ b/drivers/gpu/drm/nouveau/nv50_display.c
@@ -50,6 +50,29 @@ nv50_sor_nr(struct drm_device *dev)
 	return 4;
 }
 
+u32
+nv50_display_active_crtcs(struct drm_device *dev)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	u32 mask = 0;
+	int i;
+
+	if (dev_priv->chipset  < 0x90 ||
+	    dev_priv->chipset == 0x92 ||
+	    dev_priv->chipset == 0xa0) {
+		for (i = 0; i < 2; i++)
+			mask |= nv_rd32(dev, NV50_PDISPLAY_SOR_MODE_CTRL_C(i));
+	} else {
+		for (i = 0; i < 4; i++)
+			mask |= nv_rd32(dev, NV90_PDISPLAY_SOR_MODE_CTRL_C(i));
+	}
+
+	for (i = 0; i < 3; i++)
+		mask |= nv_rd32(dev, NV50_PDISPLAY_DAC_MODE_CTRL_C(i));
+
+	return mask & 3;
+}
+
 static int
 evo_icmd(struct drm_device *dev, int ch, u32 mthd, u32 data)
 {
diff --git a/drivers/gpu/drm/nouveau/nv50_display.h b/drivers/gpu/drm/nouveau/nv50_display.h
index 95874f7c043cf3aad9e80de35712cc9d1aad72f6..5d3dd14d2837c99023e96e8eb950a56031800678 100644
--- a/drivers/gpu/drm/nouveau/nv50_display.h
+++ b/drivers/gpu/drm/nouveau/nv50_display.h
@@ -74,6 +74,8 @@ void nv50_display_destroy(struct drm_device *dev);
 int nv50_crtc_blank(struct nouveau_crtc *, bool blank);
 int nv50_crtc_set_clock(struct drm_device *, int head, int pclk);
 
+u32  nv50_display_active_crtcs(struct drm_device *);
+
 int  nv50_display_sync(struct drm_device *);
 int  nv50_display_flip_next(struct drm_crtc *, struct drm_framebuffer *,
 			    struct nouveau_channel *chan);
diff --git a/drivers/gpu/drm/nouveau/nv50_pm.c b/drivers/gpu/drm/nouveau/nv50_pm.c
index 17eb3277b1a02a2508687148860a31971820fe52..109e473fd5f873e946b3753b4dcf5fbc928501ff 100644
--- a/drivers/gpu/drm/nouveau/nv50_pm.c
+++ b/drivers/gpu/drm/nouveau/nv50_pm.c
@@ -28,6 +28,7 @@
 #include "nouveau_hw.h"
 #include "nouveau_pm.h"
 #include "nouveau_hwsq.h"
+#include "nv50_display.h"
 
 enum clk_src {
 	clk_src_crystal,
@@ -535,6 +536,7 @@ calc_mclk(struct drm_device *dev, struct nouveau_pm_level *perflvl,
 	  struct nv50_pm_state *info)
 {
 	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	u32 crtc_mask = nv50_display_active_crtcs(dev);
 	struct nouveau_mem_exec_func exec = {
 		.dev = dev,
 		.precharge = mclk_precharge,
@@ -550,9 +552,8 @@ calc_mclk(struct drm_device *dev, struct nouveau_pm_level *perflvl,
 	};
 	struct hwsq_ucode *hwsq = &info->mclk_hwsq;
 	struct pll_lims pll;
-	u32 crtc_mask = 0;
 	int N, M, P;
-	int ret, i;
+	int ret;
 
 	/* use pcie refclock if possible, otherwise use mpll */
 	info->mctrl  = nv_rd32(dev, 0x004008);
@@ -569,12 +570,6 @@ calc_mclk(struct drm_device *dev, struct nouveau_pm_level *perflvl,
 		info->mcoef  = (N << 8) | M;
 	}
 
-	/* determine active crtcs */
-	for (i = 0; i < 2; i++) {
-		if (nv_rd32(dev, NV50_PDISPLAY_CRTC_C(i, CLOCK)))
-			crtc_mask |= (1 << i);
-	}
-
 	/* build the ucode which will reclock the memory for us */
 	hwsq_init(hwsq);
 	if (crtc_mask) {