drm/i915: preserve user forcewake over system suspend/resume

Atm, the forcewake refcount will be incorrectly set to zero during
system suspend if there is any reference held via the
i915_forcewake_user debugfs entry.

Fix this by simply not zeroing the sw counters during suspend and
restoring the original state using them. Note that the only other
places where we zeroed the counters were driver load and unload time,
where it was redundant anyway.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=78059
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -600,7 +600,7 @@ static int i915_drm_thaw_early(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
-	intel_uncore_early_sanitize(dev);
+	intel_uncore_early_sanitize(dev, true);
 	intel_uncore_sanitize(dev);
 	intel_power_domains_init_hw(dev_priv);
 

drivers/gpu/drm/i915/i915_drv.h

@@ -2078,7 +2078,8 @@ extern void intel_irq_init(struct drm_device *dev);
 extern void intel_hpd_init(struct drm_device *dev);
 
 extern void intel_uncore_sanitize(struct drm_device *dev);
-extern void intel_uncore_early_sanitize(struct drm_device *dev);
+extern void intel_uncore_early_sanitize(struct drm_device *dev,
+					bool restore_forcewake);
 extern void intel_uncore_init(struct drm_device *dev);
 extern void intel_uncore_check_errors(struct drm_device *dev);
 extern void intel_uncore_fini(struct drm_device *dev);

drivers/gpu/drm/i915/intel_uncore.c

@@ -358,16 +358,12 @@ static void intel_uncore_forcewake_reset(struct drm_device *dev, bool restore)
 			dev_priv->uncore.fifo_count =
 				__raw_i915_read32(dev_priv, GTFIFOCTL) &
 				GT_FIFO_FREE_ENTRIES_MASK;
-	} else {
-		dev_priv->uncore.forcewake_count = 0;
-		dev_priv->uncore.fw_rendercount = 0;
-		dev_priv->uncore.fw_mediacount = 0;
 	}
 
 	spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
 }
 
-void intel_uncore_early_sanitize(struct drm_device *dev)
+void intel_uncore_early_sanitize(struct drm_device *dev, bool restore_forcewake)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
@@ -390,7 +386,7 @@ void intel_uncore_early_sanitize(struct drm_device *dev)
 		__raw_i915_write32(dev_priv, GTFIFODBG,
 				   __raw_i915_read32(dev_priv, GTFIFODBG));
 
-	intel_uncore_forcewake_reset(dev, false);
+	intel_uncore_forcewake_reset(dev, restore_forcewake);
 }
 
 void intel_uncore_sanitize(struct drm_device *dev)
@@ -821,7 +817,7 @@ void intel_uncore_init(struct drm_device *dev)
 	setup_timer(&dev_priv->uncore.force_wake_timer,
 		    gen6_force_wake_timer, (unsigned long)dev_priv);
 
-	intel_uncore_early_sanitize(dev);
+	intel_uncore_early_sanitize(dev, false);
 
 	if (IS_VALLEYVIEW(dev)) {
 		dev_priv->uncore.funcs.force_wake_get = __vlv_force_wake_get;