Merge tag 'drm-intel-fixes-2015-10-01' of git://anongit.freedesktop.org/drm-intel into drm-fixes

a few i915 fixes for v4.3.

* tag 'drm-intel-fixes-2015-10-01' of git://anongit.freedesktop.org/drm-intel:
  drm/i915: Call non-locking version of drm_kms_helper_poll_enable(), v2
  drm: Add a non-locking version of drm_kms_helper_poll_enable(), v2
  drm/i915: Consider HW CSB write pointer before resetting the sw read pointer
  drm/i915/skl: Don't call intel_prepare_ddi when encoder list isn't yet initialized.

5 files changed, 53 insertions, 12 deletions

diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index d734780b31c0..a18164f2f6d2 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -94,7 +94,18 @@ static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
 }
 
 #define DRM_OUTPUT_POLL_PERIOD (10*HZ)
-static void __drm_kms_helper_poll_enable(struct drm_device *dev)
+/**
+ * drm_kms_helper_poll_enable_locked - re-enable output polling.
+ * @dev: drm_device
+ *
+ * This function re-enables the output polling work without
+ * locking the mode_config mutex.
+ *
+ * This is like drm_kms_helper_poll_enable() however it is to be
+ * called from a context where the mode_config mutex is locked
+ * already.
+ */
+void drm_kms_helper_poll_enable_locked(struct drm_device *dev)
 {
 	bool poll = false;
 	struct drm_connector *connector;
@@ -113,6 +124,8 @@ static void __drm_kms_helper_poll_enable(struct drm_device *dev)
 	if (poll)
 		schedule_delayed_work(&dev->mode_config.output_poll_work, DRM_OUTPUT_POLL_PERIOD);
 }
+EXPORT_SYMBOL(drm_kms_helper_poll_enable_locked);
+
 
 static int drm_helper_probe_single_connector_modes_merge_bits(struct drm_connector *connector,
 							      uint32_t maxX, uint32_t maxY, bool merge_type_bits)
@@ -174,7 +187,7 @@ static int drm_helper_probe_single_connector_modes_merge_bits(struct drm_connect
 
 	/* Re-enable polling in case the global poll config changed. */
 	if (drm_kms_helper_poll != dev->mode_config.poll_running)
-		__drm_kms_helper_poll_enable(dev);
+		drm_kms_helper_poll_enable_locked(dev);
 
 	dev->mode_config.poll_running = drm_kms_helper_poll;
 
@@ -428,7 +441,7 @@ EXPORT_SYMBOL(drm_kms_helper_poll_disable);
 void drm_kms_helper_poll_enable(struct drm_device *dev)
 {
 	mutex_lock(&dev->mode_config.mutex);
-	__drm_kms_helper_poll_enable(dev);
+	drm_kms_helper_poll_enable_locked(dev);
 	mutex_unlock(&dev->mode_config.mutex);
 }
 EXPORT_SYMBOL(drm_kms_helper_poll_enable);
diff --git a/drivers/gpu/drm/i915/intel_hotplug.c b/drivers/gpu/drm/i915/intel_hotplug.c
index 53c0173a39fe..b17785719598 100644
--- a/drivers/gpu/drm/i915/intel_hotplug.c
+++ b/drivers/gpu/drm/i915/intel_hotplug.c
@@ -180,7 +180,7 @@ static void intel_hpd_irq_storm_disable(struct drm_i915_private *dev_priv)
 
 	/* Enable polling and queue hotplug re-enabling. */
 	if (hpd_disabled) {
-		drm_kms_helper_poll_enable(dev);
+		drm_kms_helper_poll_enable_locked(dev);
 		mod_delayed_work(system_wq, &dev_priv->hotplug.reenable_work,
 				 msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
 	}
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 72e0edd7bbde..7412caedcf7f 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -484,18 +484,18 @@ void intel_lrc_irq_handler(struct intel_engine_cs *ring)
 	status_pointer = I915_READ(RING_CONTEXT_STATUS_PTR(ring));
 
 	read_pointer = ring->next_context_status_buffer;
-	write_pointer = status_pointer & 0x07;
+	write_pointer = status_pointer & GEN8_CSB_PTR_MASK;
 	if (read_pointer > write_pointer)
-		write_pointer += 6;
+		write_pointer += GEN8_CSB_ENTRIES;
 
 	spin_lock(&ring->execlist_lock);
 
 	while (read_pointer < write_pointer) {
 		read_pointer++;
 		status = I915_READ(RING_CONTEXT_STATUS_BUF(ring) +
-				(read_pointer % 6) * 8);
+				(read_pointer % GEN8_CSB_ENTRIES) * 8);
 		status_id = I915_READ(RING_CONTEXT_STATUS_BUF(ring) +
-				(read_pointer % 6) * 8 + 4);
+				(read_pointer % GEN8_CSB_ENTRIES) * 8 + 4);
 
 		if (status & GEN8_CTX_STATUS_IDLE_ACTIVE)
 			continue;
@@ -521,10 +521,12 @@ void intel_lrc_irq_handler(struct intel_engine_cs *ring)
 	spin_unlock(&ring->execlist_lock);
 
 	WARN(submit_contexts > 2, "More than two context complete events?\n");
-	ring->next_context_status_buffer = write_pointer % 6;
+	ring->next_context_status_buffer = write_pointer % GEN8_CSB_ENTRIES;
 
 	I915_WRITE(RING_CONTEXT_STATUS_PTR(ring),
-		   _MASKED_FIELD(0x07 << 8, ((u32)ring->next_context_status_buffer & 0x07) << 8));
+		   _MASKED_FIELD(GEN8_CSB_PTR_MASK << 8,
+				 ((u32)ring->next_context_status_buffer &
+				  GEN8_CSB_PTR_MASK) << 8));
 }
 
 static int execlists_context_queue(struct drm_i915_gem_request *request)
@@ -1422,6 +1424,7 @@ static int gen8_init_common_ring(struct intel_engine_cs *ring)
 {
 	struct drm_device *dev = ring->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
+	u8 next_context_status_buffer_hw;
 
 	I915_WRITE_IMR(ring, ~(ring->irq_enable_mask | ring->irq_keep_mask));
 	I915_WRITE(RING_HWSTAM(ring->mmio_base), 0xffffffff);
@@ -1436,7 +1439,29 @@ static int gen8_init_common_ring(struct intel_engine_cs *ring)
 		   _MASKED_BIT_DISABLE(GFX_REPLAY_MODE) |
 		   _MASKED_BIT_ENABLE(GFX_RUN_LIST_ENABLE));
 	POSTING_READ(RING_MODE_GEN7(ring));
-	ring->next_context_status_buffer = 0;
+
+	/*
+	 * Instead of resetting the Context Status Buffer (CSB) read pointer to
+	 * zero, we need to read the write pointer from hardware and use its
+	 * value because "this register is power context save restored".
+	 * Effectively, these states have been observed:
+	 *
+	 *      | Suspend-to-idle (freeze) | Suspend-to-RAM (mem) |
+	 * BDW  | CSB regs not reset       | CSB regs reset       |
+	 * CHT  | CSB regs not reset       | CSB regs not reset   |
+	 */
+	next_context_status_buffer_hw = (I915_READ(RING_CONTEXT_STATUS_PTR(ring))
+						   & GEN8_CSB_PTR_MASK);
+
+	/*
+	 * When the CSB registers are reset (also after power-up / gpu reset),
+	 * CSB write pointer is set to all 1's, which is not valid, use '5' in
+	 * this special case, so the first element read is CSB[0].
+	 */
+	if (next_context_status_buffer_hw == GEN8_CSB_PTR_MASK)
+		next_context_status_buffer_hw = (GEN8_CSB_ENTRIES - 1);
+
+	ring->next_context_status_buffer = next_context_status_buffer_hw;
 	DRM_DEBUG_DRIVER("Execlists enabled for %s\n", ring->name);
 
 	memset(&ring->hangcheck, 0, sizeof(ring->hangcheck));
diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.h
index 64f89f9982a2..3c63bb32ad81 100644
--- a/drivers/gpu/drm/i915/intel_lrc.h
+++ b/drivers/gpu/drm/i915/intel_lrc.h
@@ -25,6 +25,8 @@
 #define _INTEL_LRC_H_
 
 #define GEN8_LR_CONTEXT_ALIGN 4096
+#define GEN8_CSB_ENTRIES 6
+#define GEN8_CSB_PTR_MASK 0x07
 
 /* Execlists regs */
 #define RING_ELSP(ring)			((ring)->mmio_base+0x230)
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index af7fdb3bd663..7401cf90b0db 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -246,7 +246,8 @@ static void skl_power_well_post_enable(struct drm_i915_private *dev_priv,
 	}
 
 	if (power_well->data == SKL_DISP_PW_1) {
-		intel_prepare_ddi(dev);
+		if (!dev_priv->power_domains.initializing)
+			intel_prepare_ddi(dev);
 		gen8_irq_power_well_post_enable(dev_priv, 1 << PIPE_A);
 	}
 }