drm/i915: forcewake struct mutex locking fixes

Found by the new strict checking for the mutex being held whilst
manipulating the forcewake status.
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Keith Packard <keithp@keithp.com>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -853,6 +853,7 @@ static int i915_cur_delayinfo(struct seq_file *m, void *unused)
 	struct drm_info_node *node = (struct drm_info_node *) m->private;
 	struct drm_device *dev = node->minor->dev;
 	drm_i915_private_t *dev_priv = dev->dev_private;
+	int ret;
 
 	if (IS_GEN5(dev)) {
 		u16 rgvswctl = I915_READ16(MEMSWCTL);
@@ -874,6 +875,10 @@ static int i915_cur_delayinfo(struct seq_file *m, void *unused)
 		int max_freq;
 
 		/* RPSTAT1 is in the GT power well */
+		ret = mutex_lock_interruptible(&dev->struct_mutex);
+		if (ret)
+			return ret;
+
 		gen6_gt_force_wake_get(dev_priv);
 
 		rpstat = I915_READ(GEN6_RPSTAT1);
@@ -884,6 +889,9 @@ static int i915_cur_delayinfo(struct seq_file *m, void *unused)
 		rpcurdown = I915_READ(GEN6_RP_CUR_DOWN);
 		rpprevdown = I915_READ(GEN6_RP_PREV_DOWN);
 
+		gen6_gt_force_wake_put(dev_priv);
+		mutex_unlock(&dev->struct_mutex);
+
 		seq_printf(m, "GT_PERF_STATUS: 0x%08x\n", gt_perf_status);
 		seq_printf(m, "RPSTAT1: 0x%08x\n", rpstat);
 		seq_printf(m, "Render p-state ratio: %d\n",
@@ -918,8 +926,6 @@ static int i915_cur_delayinfo(struct seq_file *m, void *unused)
 		max_freq = rp_state_cap & 0xff;
 		seq_printf(m, "Max non-overclocked (RP0) frequency: %dMHz\n",
 			   max_freq * 50);
-
-		gen6_gt_force_wake_put(dev_priv);
 	} else {
 		seq_printf(m, "no P-state info available\n");
 	}

drivers/gpu/drm/i915/intel_display.c

@@ -2585,7 +2585,11 @@ static void ironlake_crtc_enable(struct drm_crtc *crtc)
 		ironlake_pch_enable(crtc);
 
 	intel_crtc_load_lut(crtc);
+
+	mutex_lock(&dev->struct_mutex);
 	intel_update_fbc(dev);
+	mutex_unlock(&dev->struct_mutex);
+
 	intel_crtc_update_cursor(crtc, true);
 }
 
@@ -2681,8 +2685,11 @@ static void ironlake_crtc_disable(struct drm_crtc *crtc)
 
 	intel_crtc->active = false;
 	intel_update_watermarks(dev);
+
+	mutex_lock(&dev->struct_mutex);
 	intel_update_fbc(dev);
 	intel_clear_scanline_wait(dev);
+	mutex_unlock(&dev->struct_mutex);
 }
 
 static void ironlake_crtc_dpms(struct drm_crtc *crtc, int mode)
@@ -6973,6 +6980,7 @@ void gen6_enable_rps(struct drm_i915_private *dev_priv)
 	 * userspace...
 	 */
 	I915_WRITE(GEN6_RC_STATE, 0);
+	mutex_lock(&dev_priv->dev->struct_mutex);
 	gen6_gt_force_wake_get(dev_priv);
 
 	/* disable the counters and set deterministic thresholds */
@@ -7075,6 +7083,7 @@ void gen6_enable_rps(struct drm_i915_private *dev_priv)
 	I915_WRITE(GEN6_PMINTRMSK, 0);
 
 	gen6_gt_force_wake_put(dev_priv);
+	mutex_unlock(&dev_priv->dev->struct_mutex);
 }
 
 void intel_enable_clock_gating(struct drm_device *dev)