Merge tag 'drm-intel-next-fixes-2018-03-27' of git://anongit.freedesktop.org/drm/drm-intel into drm-next

- Display fixes for booting with MST hub lid closed and display
  freezing after hibernation (fd.o bugs 105470 & 105196)
- Fix for a very rare interrupt handling race resulting in GPU hang

* tag 'drm-intel-next-fixes-2018-03-27' of git://anongit.freedesktop.org/drm/drm-intel:
  drm/i915: Fix hibernation with ACPI S0 target state
  drm/i915/execlists: Use a locked clear_bit() for synchronisation with interrupt
  drm/i915: Specify which engines to reset following semaphore/event lockups
  drm/i915/dp: Write to SET_POWER dpcd to enable MST hub.

drivers/gpu/drm/i915/i915_drv.c

@@ -1611,15 +1611,12 @@ static int i915_drm_suspend_late(struct drm_device *dev, bool hibernation)
 {
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct pci_dev *pdev = dev_priv->drm.pdev;
-	bool fw_csr;
 	int ret;
 
 	disable_rpm_wakeref_asserts(dev_priv);
 
 	intel_display_set_init_power(dev_priv, false);
 
-	fw_csr = !IS_GEN9_LP(dev_priv) && !hibernation &&
-		suspend_to_idle(dev_priv) && dev_priv->csr.dmc_payload;
 	/*
 	 * In case of firmware assisted context save/restore don't manually
 	 * deinit the power domains. This also means the CSR/DMC firmware will
@@ -1627,8 +1624,11 @@ static int i915_drm_suspend_late(struct drm_device *dev, bool hibernation)
 	 * also enable deeper system power states that would be blocked if the
 	 * firmware was inactive.
 	 */
-	if (!fw_csr)
+	if (IS_GEN9_LP(dev_priv) || hibernation || !suspend_to_idle(dev_priv) ||
+	    dev_priv->csr.dmc_payload == NULL) {
 		intel_power_domains_suspend(dev_priv);
+		dev_priv->power_domains_suspended = true;
+	}
 
 	ret = 0;
 	if (IS_GEN9_LP(dev_priv))
@@ -1640,8 +1640,10 @@ static int i915_drm_suspend_late(struct drm_device *dev, bool hibernation)
 
 	if (ret) {
 		DRM_ERROR("Suspend complete failed: %d\n", ret);
-		if (!fw_csr)
+		if (dev_priv->power_domains_suspended) {
 			intel_power_domains_init_hw(dev_priv, true);
+			dev_priv->power_domains_suspended = false;
+		}
 
 		goto out;
 	}
@@ -1662,8 +1664,6 @@ static int i915_drm_suspend_late(struct drm_device *dev, bool hibernation)
 	if (!(hibernation && INTEL_GEN(dev_priv) < 6))
 		pci_set_power_state(pdev, PCI_D3hot);
 
-	dev_priv->suspended_to_idle = suspend_to_idle(dev_priv);
-
 out:
 	enable_rpm_wakeref_asserts(dev_priv);
 
@@ -1830,8 +1830,7 @@ static int i915_drm_resume_early(struct drm_device *dev)
 	intel_uncore_resume_early(dev_priv);
 
 	if (IS_GEN9_LP(dev_priv)) {
-		if (!dev_priv->suspended_to_idle)
-			gen9_sanitize_dc_state(dev_priv);
+		gen9_sanitize_dc_state(dev_priv);
 		bxt_disable_dc9(dev_priv);
 	} else if (IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv)) {
 		hsw_disable_pc8(dev_priv);
@@ -1839,8 +1838,7 @@ static int i915_drm_resume_early(struct drm_device *dev)
 
 	intel_uncore_sanitize(dev_priv);
 
-	if (IS_GEN9_LP(dev_priv) ||
-	    !(dev_priv->suspended_to_idle && dev_priv->csr.dmc_payload))
+	if (dev_priv->power_domains_suspended)
 		intel_power_domains_init_hw(dev_priv, true);
 	else
 		intel_display_set_init_power(dev_priv, true);
@@ -1850,7 +1848,7 @@ static int i915_drm_resume_early(struct drm_device *dev)
 	enable_rpm_wakeref_asserts(dev_priv);
 
 out:
-	dev_priv->suspended_to_idle = false;
+	dev_priv->power_domains_suspended = false;
 
 	return ret;
 }

drivers/gpu/drm/i915/i915_drv.h

@@ -2119,7 +2119,7 @@ struct drm_i915_private {
 	u32 bxt_phy_grc;
 
 	u32 suspend_count;
-	bool suspended_to_idle;
+	bool power_domains_suspended;
 	struct i915_suspend_saved_registers regfile;
 	struct vlv_s0ix_state vlv_s0ix_state;
 

drivers/gpu/drm/i915/intel_lrc.c

@@ -831,7 +831,8 @@ static void execlists_submission_tasklet(unsigned long data)
 	struct drm_i915_private *dev_priv = engine->i915;
 	bool fw = false;
 
-	/* We can skip acquiring intel_runtime_pm_get() here as it was taken
+	/*
+	 * We can skip acquiring intel_runtime_pm_get() here as it was taken
 	 * on our behalf by the request (see i915_gem_mark_busy()) and it will
 	 * not be relinquished until the device is idle (see
 	 * i915_gem_idle_work_handler()). As a precaution, we make sure
@@ -840,7 +841,8 @@ static void execlists_submission_tasklet(unsigned long data)
 	 */
 	GEM_BUG_ON(!dev_priv->gt.awake);
 
-	/* Prefer doing test_and_clear_bit() as a two stage operation to avoid
+	/*
+	 * Prefer doing test_and_clear_bit() as a two stage operation to avoid
 	 * imposing the cost of a locked atomic transaction when submitting a
 	 * new request (outside of the context-switch interrupt).
 	 */
@@ -856,17 +858,10 @@ static void execlists_submission_tasklet(unsigned long data)
 			execlists->csb_head = -1; /* force mmio read of CSB ptrs */
 		}
 
-		/* The write will be ordered by the uncached read (itself
-		 * a memory barrier), so we do not need another in the form
-		 * of a locked instruction. The race between the interrupt
-		 * handler and the split test/clear is harmless as we order
-		 * our clear before the CSB read. If the interrupt arrived
-		 * first between the test and the clear, we read the updated
-		 * CSB and clear the bit. If the interrupt arrives as we read
-		 * the CSB or later (i.e. after we had cleared the bit) the bit
-		 * is set and we do a new loop.
-		 */
-		__clear_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted);
+		/* Clear before reading to catch new interrupts */
+		clear_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted);
+		smp_mb__after_atomic();
+
 		if (unlikely(execlists->csb_head == -1)) { /* following a reset */
 			if (!fw) {
 				intel_uncore_forcewake_get(dev_priv,