drm/i915/hsw, bdw: Remove redundant state check during power well toggling

Similarly to the GEN9 power well toggling, saving an occasional extra
MMIO write is not worth the code complexity, let's simplify things.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1499352040-8819-11-git-send-email-imre.deak@intel.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_runtime_pm.c

@@ -399,36 +399,26 @@ static void gen9_wait_for_power_well_disable(struct drm_i915_private *dev_priv,
 static void hsw_set_power_well(struct drm_i915_private *dev_priv,
 			       struct i915_power_well *power_well, bool enable)
 {
-	bool is_enabled, enable_requested;
 	uint32_t tmp;
 
 	tmp = I915_READ(HSW_PWR_WELL_DRIVER);
-	is_enabled = tmp & HSW_PWR_WELL_STATE_ENABLED;
-	enable_requested = tmp & HSW_PWR_WELL_ENABLE_REQUEST;
 
 	if (enable) {
-		if (!enable_requested)
-			I915_WRITE(HSW_PWR_WELL_DRIVER,
-				   HSW_PWR_WELL_ENABLE_REQUEST);
-
-		if (!is_enabled) {
-			DRM_DEBUG_KMS("Enabling power well\n");
-			if (intel_wait_for_register(dev_priv,
-						    HSW_PWR_WELL_DRIVER,
-						    HSW_PWR_WELL_STATE_ENABLED,
-						    HSW_PWR_WELL_STATE_ENABLED,
-						    20))
-				DRM_ERROR("Timeout enabling power well\n");
-			hsw_power_well_post_enable(dev_priv);
-		}
+		I915_WRITE(HSW_PWR_WELL_DRIVER, HSW_PWR_WELL_ENABLE_REQUEST);
 
+		DRM_DEBUG_KMS("Enabling power well\n");
+		if (intel_wait_for_register(dev_priv,
+					    HSW_PWR_WELL_DRIVER,
+					    HSW_PWR_WELL_STATE_ENABLED,
+					    HSW_PWR_WELL_STATE_ENABLED,
+					    20))
+			DRM_ERROR("Timeout enabling power well\n");
+		hsw_power_well_post_enable(dev_priv);
 	} else {
-		if (enable_requested) {
-			hsw_power_well_pre_disable(dev_priv);
-			I915_WRITE(HSW_PWR_WELL_DRIVER, 0);
-			POSTING_READ(HSW_PWR_WELL_DRIVER);
-			DRM_DEBUG_KMS("Requesting to disable the power well\n");
-		}
+		hsw_power_well_pre_disable(dev_priv);
+		I915_WRITE(HSW_PWR_WELL_DRIVER, 0);
+		POSTING_READ(HSW_PWR_WELL_DRIVER);
+		DRM_DEBUG_KMS("Requesting to disable the power well\n");
 	}
 }