drm/i915 more registers for S3 (DSPCLK_GATE_D, CACHE_MODE_0, MI_ARB_STATE)

Failing to preserve the MI_ARB_STATE register was causing FIFO underruns on
the VGA output on my HP 2510p after resume.
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/char/drm/i915_drv.c

@@ -342,6 +342,15 @@ static int i915_suspend(struct drm_device *dev)
 	dev_priv->saveVCLK_POST_DIV = I915_READ(VCLK_POST_DIV);
 	dev_priv->saveVGACNTRL = I915_READ(VGACNTRL);
 
+	/* Clock gating state */
+	dev_priv->saveDSPCLK_GATE_D = I915_READ(DSPCLK_GATE_D);
+
+	/* Cache mode state */
+	dev_priv->saveCACHE_MODE_0 = I915_READ(CACHE_MODE_0);
+
+	/* Memory Arbitration state */
+	dev_priv->saveMI_ARB_STATE = I915_READ(MI_ARB_STATE);
+
 	/* Scratch space */
 	for (i = 0; i < 16; i++) {
 		dev_priv->saveSWF0[i] = I915_READ(SWF0 + (i << 2));
@@ -489,6 +498,15 @@ static int i915_resume(struct drm_device *dev)
 	I915_WRITE(VCLK_POST_DIV, dev_priv->saveVCLK_POST_DIV);
 	udelay(150);
 
+	/* Clock gating state */
+	I915_WRITE (DSPCLK_GATE_D, dev_priv->saveDSPCLK_GATE_D);
+
+	/* Cache mode state */
+	I915_WRITE (CACHE_MODE_0, dev_priv->saveCACHE_MODE_0 | 0xffff0000);
+
+	/* Memory arbitration state */
+	I915_WRITE (MI_ARB_STATE, dev_priv->saveMI_ARB_STATE | 0xffff0000);
+
 	for (i = 0; i < 16; i++) {
 		I915_WRITE(SWF0 + (i << 2), dev_priv->saveSWF0[i]);
 		I915_WRITE(SWF10 + (i << 2), dev_priv->saveSWF1[i+7]);

drivers/char/drm/i915_drv.h

@@ -187,6 +187,9 @@ typedef struct drm_i915_private {
 	u32 saveIER;
 	u32 saveIIR;
 	u32 saveIMR;
+	u32 saveCACHE_MODE_0;
+	u32 saveDSPCLK_GATE_D;
+	u32 saveMI_ARB_STATE;
 	u32 saveSWF0[16];
 	u32 saveSWF1[16];
 	u32 saveSWF2[3];
@@ -455,6 +458,10 @@ extern int i915_wait_ring(struct drm_device * dev, int n, const char *caller);
  */
 #define DMA_FADD_S		0x20d4
 
+/* Memory Interface Arbitration State
+ */
+#define MI_ARB_STATE		0x20e4
+
 /* Cache mode 0 reg.
  *  - Manipulating render cache behaviour is central
  *    to the concept of zone rendering, tuning this reg can help avoid
@@ -465,6 +472,7 @@ extern int i915_wait_ring(struct drm_device * dev, int n, const char *caller);
  * bit of interest either set or cleared.  EG: (BIT<<16) | BIT to set.
  */
 #define Cache_Mode_0		0x2120
+#define CACHE_MODE_0		0x2120
 #define CM0_MASK_SHIFT          16
 #define CM0_IZ_OPT_DISABLE      (1<<6)
 #define CM0_ZR_OPT_DISABLE      (1<<5)
@@ -660,6 +668,8 @@ extern int i915_wait_ring(struct drm_device * dev, int n, const char *caller);
 /** P1 value is 2 greater than this field */
 # define VGA0_PD_P1_MASK	(0x1f << 0)
 
+#define DSPCLK_GATE_D	0x6200
+
 /* I830 CRTC registers */
 #define HTOTAL_A	0x60000
 #define HBLANK_A	0x60004