drm/i915: Fix Sandybridge fence registers

With 5 places to update when adding handling for fence registers, it is
easy to overlook one or two. Correct that oversight, but fence
management should be improved before a new set of registers is added.

Bugzilla: https://bugs.freedesktop.org/show_bug?id=30199
Original patch by: Yuanhan Liu <yuanhan.liu@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org

drivers/gpu/drm/i915/i915_gem.c

@@ -2351,14 +2351,21 @@ i915_gem_object_get_fence_reg(struct drm_gem_object *obj)
 
 	reg->obj = obj;
 
-	if (IS_GEN6(dev))
+	switch (INTEL_INFO(dev)->gen) {
+	case 6:
 		sandybridge_write_fence_reg(reg);
-	else if (IS_I965G(dev))
+		break;
+	case 5:
+	case 4:
 		i965_write_fence_reg(reg);
-	else if (IS_I9XX(dev))
+		break;
+	case 3:
 		i915_write_fence_reg(reg);
-	else
+		break;
+	case 2:
 		i830_write_fence_reg(reg);
+		break;
+	}
 
 	trace_i915_gem_object_get_fence(obj, obj_priv->fence_reg,
 			obj_priv->tiling_mode);
@@ -2381,22 +2388,26 @@ i915_gem_clear_fence_reg(struct drm_gem_object *obj)
 	struct drm_i915_gem_object *obj_priv = to_intel_bo(obj);
 	struct drm_i915_fence_reg *reg =
 		&dev_priv->fence_regs[obj_priv->fence_reg];
+	uint32_t fence_reg;
 
-	if (IS_GEN6(dev)) {
+	switch (INTEL_INFO(dev)->gen) {
+	case 6:
 		I915_WRITE64(FENCE_REG_SANDYBRIDGE_0 +
 			     (obj_priv->fence_reg * 8), 0);
-	} else if (IS_I965G(dev)) {
+		break;
+	case 5:
+	case 4:
 		I915_WRITE64(FENCE_REG_965_0 + (obj_priv->fence_reg * 8), 0);
-	} else {
-		uint32_t fence_reg;
-
-		if (obj_priv->fence_reg < 8)
-			fence_reg = FENCE_REG_830_0 + obj_priv->fence_reg * 4;
+		break;
+	case 3:
+		if (obj_priv->fence_reg > 8)
+			fence_reg = FENCE_REG_945_8 + (obj_priv->fence_reg - 8) * 4;
 		else
-			fence_reg = FENCE_REG_945_8 + (obj_priv->fence_reg -
-						       8) * 4;
+	case 2:
+			fence_reg = FENCE_REG_830_0 + obj_priv->fence_reg * 4;
 
 		I915_WRITE(fence_reg, 0);
+		break;
 	}
 
 	reg->obj = NULL;

drivers/gpu/drm/i915/i915_suspend.c

@@ -789,16 +789,25 @@ int i915_save_state(struct drm_device *dev)
 		dev_priv->saveSWF2[i] = I915_READ(SWF30 + (i << 2));
 
 	/* Fences */
-	if (IS_I965G(dev)) {
+	switch (INTEL_INFO(dev)->gen) {
+	case 6:
+		for (i = 0; i < 16; i++)
+			dev_priv->saveFENCE[i] = I915_READ64(FENCE_REG_SANDYBRIDGE_0 + (i * 8));
+		break;
+	case 5:
+	case 4:
 		for (i = 0; i < 16; i++)
 			dev_priv->saveFENCE[i] = I915_READ64(FENCE_REG_965_0 + (i * 8));
-	} else {
-		for (i = 0; i < 8; i++)
-			dev_priv->saveFENCE[i] = I915_READ(FENCE_REG_830_0 + (i * 4));
-
+		break;
+	case 3:
 		if (IS_I945G(dev) || IS_I945GM(dev) || IS_G33(dev))
 			for (i = 0; i < 8; i++)
 				dev_priv->saveFENCE[i+8] = I915_READ(FENCE_REG_945_8 + (i * 4));
+	case 2:
+		for (i = 0; i < 8; i++)
+			dev_priv->saveFENCE[i] = I915_READ(FENCE_REG_830_0 + (i * 4));
+		break;
+
 	}
 
 	return 0;
@@ -815,15 +824,24 @@ int i915_restore_state(struct drm_device *dev)
 	I915_WRITE(HWS_PGA, dev_priv->saveHWS);
 
 	/* Fences */
-	if (IS_I965G(dev)) {
+	switch (INTEL_INFO(dev)->gen) {
+	case 6:
+		for (i = 0; i < 16; i++)
+			I915_WRITE64(FENCE_REG_SANDYBRIDGE_0 + (i * 8), dev_priv->saveFENCE[i]);
+		break;
+	case 5:
+	case 4:
 		for (i = 0; i < 16; i++)
 			I915_WRITE64(FENCE_REG_965_0 + (i * 8), dev_priv->saveFENCE[i]);
-	} else {
-		for (i = 0; i < 8; i++)
-			I915_WRITE(FENCE_REG_830_0 + (i * 4), dev_priv->saveFENCE[i]);
+		break;
+	case 3:
+	case 2:
 		if (IS_I945G(dev) || IS_I945GM(dev) || IS_G33(dev))
 			for (i = 0; i < 8; i++)
 				I915_WRITE(FENCE_REG_945_8 + (i * 4), dev_priv->saveFENCE[i+8]);
+		for (i = 0; i < 8; i++)
+			I915_WRITE(FENCE_REG_830_0 + (i * 4), dev_priv->saveFENCE[i]);
+		break;
 	}
 
 	i915_restore_display(dev);