[PATCH v6 1/4] drm/i915/vlv: Make intel_crt_reset() per-encoder

[PATCH v6 1/4] drm/i915/vlv: Make intel_crt_reset() per-encoder

[Lyude]

This lets call intel_crt_reset() in contexts where IRQs are disabled and
as such, can't hold the locks required to work with the connectors.

Cc: stable@vger.kernel.org
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Lyude <cpaul@redhat.com>
---
 drivers/gpu/drm/i915/intel_crt.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index e115bcc..dfcd718 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -713,11 +713,11 @@ static int intel_crt_set_property(struct drm_connector *connector,
 	return 0;
 }
 
-static void intel_crt_reset(struct drm_connector *connector)
+static void intel_crt_reset(struct drm_encoder *encoder)
 {
-	struct drm_device *dev = connector->dev;
+	struct drm_device *dev = encoder->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct intel_crt *crt = intel_attached_crt(connector);
+	struct intel_crt *crt = intel_encoder_to_crt(to_intel_encoder(encoder));
 
 	if (INTEL_INFO(dev)->gen >= 5) {
 		u32 adpa;
@@ -739,7 +739,6 @@ static void intel_crt_reset(struct drm_connector *connector)
  */
 
 static const struct drm_connector_funcs intel_crt_connector_funcs = {
-	.reset = intel_crt_reset,
 	.dpms = drm_atomic_helper_connector_dpms,
 	.detect = intel_crt_detect,
 	.fill_modes = drm_helper_probe_single_connector_modes,
@@ -757,6 +756,7 @@ static const struct drm_connector_helper_funcs intel_crt_connector_helper_funcs
 };
 
 static const struct drm_encoder_funcs intel_crt_enc_funcs = {
+	.reset = intel_crt_reset,
 	.destroy = intel_encoder_destroy,
 };
 
@@ -901,5 +901,5 @@ void intel_crt_init(struct drm_device *dev)
 		dev_priv->fdi_rx_config = I915_READ(FDI_RX_CTL(PIPE_A)) & fdi_config;
 	}
 
-	intel_crt_reset(connector);
+	intel_crt_reset(&crt->base.base);
 }
-- 
2.5.5

[PATCH v6 2/4] drm/i915/vlv: Reset the ADPA in vlv_display_power_well_init()

[Lyude]

While VGA hotplugging worked(ish) before, it looks like that was mainly
because we'd unintentionally enable it in
valleyview_crt_detect_hotplug() when we did a force trigger. This
doesn't work reliably enough because whenever the display powerwell on
vlv gets disabled, the values set in VLV_ADPA get cleared and
consequently VGA hotplugging gets disabled. This causes bugs such as one
we found on an Intel NUC, where doing the following sequence of
hotplugs:

      - Disconnect all monitors
      - Connect VGA
      - Disconnect VGA
      - Connect HDMI

Would result in VGA hotplugging becoming disabled, due to the powerwells
getting toggled in the process of connecting HDMI.

Changes since v3:
 - Expose intel_crt_reset() through intel_drv.h and call that in
   vlv_display_power_well_init() instead of
   encoder->base.funcs->reset(&encoder->base);

Changes since v2:
 - Use intel_encoder structs instead of drm_encoder structs

Changes since v1:
 - Instead of handling the register writes ourself, we just reuse
   intel_crt_detect()
 - Instead of resetting the ADPA during display IRQ installation, we now
   reset them in vlv_display_power_well_init()

Cc: stable@vger.kernel.org
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Lyude <cpaul@redhat.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/intel_crt.c        | 2 +-
 drivers/gpu/drm/i915/intel_drv.h        | 2 +-
 drivers/gpu/drm/i915/intel_runtime_pm.c | 7 +++++++
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index dfcd718..220be7a 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -713,7 +713,7 @@ static int intel_crt_set_property(struct drm_connector *connector,
 	return 0;
 }
 
-static void intel_crt_reset(struct drm_encoder *encoder)
+void intel_crt_reset(struct drm_encoder *encoder)
 {
 	struct drm_device *dev = encoder->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 496c962..dcbfdde 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1075,7 +1075,7 @@ void gen8_irq_power_well_pre_disable(struct drm_i915_private *dev_priv,
 
 /* intel_crt.c */
 void intel_crt_init(struct drm_device *dev);
-
+void intel_crt_reset(struct drm_encoder *encoder);
 
 /* intel_ddi.c */
 void intel_ddi_clk_select(struct intel_encoder *encoder,
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index e856d49..f88ef76 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -1065,6 +1065,7 @@ static void vlv_init_display_clock_gating(struct drm_i915_private *dev_priv)
 
 static void vlv_display_power_well_init(struct drm_i915_private *dev_priv)
 {
+	struct intel_encoder *encoder;
 	enum pipe pipe;
 
 	/*
@@ -1100,6 +1101,12 @@ static void vlv_display_power_well_init(struct drm_i915_private *dev_priv)
 
 	intel_hpd_init(dev_priv);
 
+	/* Re-enable the ADPA, if we have one */
+	for_each_intel_encoder(dev_priv->dev, encoder) {
+		if (encoder->type == INTEL_OUTPUT_ANALOG)
+			intel_crt_reset(&encoder->base);
+	}
+
 	i915_redisable_vga_power_on(dev_priv->dev);
 }
 
-- 
2.5.5

[PATCH v6 3/4] drm/i915/vlv: Disable HPD in valleyview_crt_detect_hotplug()

[Lyude]

One of the things preventing us from using polling is the fact that
calling valleyview_crt_detect_hotplug() when there's a VGA cable
connected results in sending another hotplug. With polling enabled when
HPD is disabled, this results in a scenario like this:

- We enable power wells and reset the ADPA
- output_poll_exec does force probe on VGA, triggering a hpd
- HPD handler waits for poll to unlock dev->mode_config.mutex
- output_poll_exec shuts off the ADPA, unlocks dev->mode_config.mutex
- HPD handler runs, resets ADPA and brings us back to the start

This results in an endless irq storm getting sent from the ADPA
whenever a VGA connector gets detected in the middle of polling.

Somewhat based off of the "drm/i915: Disable CRT HPD around force
trigger" patch Ville Syrjälä sent a while back

Cc: stable@vger.kernel.org
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Lyude <cpaul@redhat.com>
---
 drivers/gpu/drm/i915/i915_drv.h      |  2 ++
 drivers/gpu/drm/i915/intel_crt.c     | 18 ++++++++++++++++++
 drivers/gpu/drm/i915/intel_hotplug.c | 27 +++++++++++++++++++++++++++
 3 files changed, 47 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index a988a95..239a3ec 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2933,6 +2933,8 @@ void intel_hpd_init(struct drm_i915_private *dev_priv);
 void intel_hpd_init_work(struct drm_i915_private *dev_priv);
 void intel_hpd_cancel_work(struct drm_i915_private *dev_priv);
 bool intel_hpd_pin_to_port(enum hpd_pin pin, enum port *port);
+bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin);
+void intel_hpd_enable(struct drm_i915_private *dev_priv, enum hpd_pin pin);
 
 /* i915_irq.c */
 void i915_queue_hangcheck(struct drm_i915_private *dev_priv);
diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index 220be7a..a626793 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -327,10 +327,25 @@ static bool valleyview_crt_detect_hotplug(struct drm_connector *connector)
 	struct drm_device *dev = connector->dev;
 	struct intel_crt *crt = intel_attached_crt(connector);
 	struct drm_i915_private *dev_priv = dev->dev_private;
+	bool reenable_hpd;
 	u32 adpa;
 	bool ret;
 	u32 save_adpa;
 
+	/*
+	 * Doing a force trigger causes a hpd interrupt to get sent, which can
+	 * get us stuck in a loop if we're polling:
+	 *  - We enable power wells and reset the ADPA
+	 *  - output_poll_exec does force probe on VGA, triggering a hpd
+	 *  - HPD handler waits for poll to unlock dev->mode_config.mutex
+	 *  - output_poll_exec shuts off the ADPA, unlocks
+	 *    dev->mode_config.mutex
+	 *  - HPD handler runs, resets ADPA and brings us back to the start
+	 *
+	 * Just disable HPD interrupts here to prevent this
+	 */
+	reenable_hpd = intel_hpd_disable(dev_priv, crt->base.hpd_pin);
+
 	save_adpa = adpa = I915_READ(crt->adpa_reg);
 	DRM_DEBUG_KMS("trigger hotplug detect cycle: adpa=0x%x\n", adpa);
 
@@ -353,6 +368,9 @@ static bool valleyview_crt_detect_hotplug(struct drm_connector *connector)
 
 	DRM_DEBUG_KMS("valleyview hotplug adpa=0x%x, result %d\n", adpa, ret);
 
+	if (reenable_hpd)
+		intel_hpd_enable(dev_priv, crt->base.hpd_pin);
+
 	return ret;
 }
 
diff --git a/drivers/gpu/drm/i915/intel_hotplug.c b/drivers/gpu/drm/i915/intel_hotplug.c
index 38eeca7..ec3285f 100644
--- a/drivers/gpu/drm/i915/intel_hotplug.c
+++ b/drivers/gpu/drm/i915/intel_hotplug.c
@@ -510,3 +510,30 @@ void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
 	cancel_work_sync(&dev_priv->hotplug.hotplug_work);
 	cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);
 }
+
+bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
+{
+	bool ret = false;
+
+	if (pin == HPD_NONE)
+		return false;
+
+	spin_lock_irq(&dev_priv->irq_lock);
+	if (dev_priv->hotplug.stats[pin].state == HPD_ENABLED) {
+		dev_priv->hotplug.stats[pin].state = HPD_DISABLED;
+		ret = true;
+	}
+	spin_unlock_irq(&dev_priv->irq_lock);
+
+	return ret;
+}
+
+void intel_hpd_enable(struct drm_i915_private *dev_priv, enum hpd_pin pin)
+{
+	if (pin == HPD_NONE)
+		return;
+
+	spin_lock_irq(&dev_priv->irq_lock);
+	dev_priv->hotplug.stats[pin].state = HPD_ENABLED;
+	spin_unlock_irq(&dev_priv->irq_lock);
+}
-- 
2.5.5

[PATCH v6 4/4] drm/i915: Enable polling when we don't have hpd

[Lyude]

Unfortunately, there's two situations where we lose hpd right now:
- Runtime suspend
- When we've shut off all of the power wells on Valleyview/Cherryview

While it would be nice if this didn't cause issues, this has the
ability to get us in some awkward states where a user won't be able to
get their display to turn on. For instance; if we boot a Valleyview
system without any monitors connected, it won't need any of it's power
wells and thus shut them off. Since this causes us to lose HPD, this
means that unless the user knows how to ssh into their machine and do a
manual reprobe for monitors, none of the monitors they connect after
booting will actually work.

Eventually we should come up with a better fix then having to enable
polling for this, since this makes rpm a lot less useful, but for now
the infrastructure in i915 just isn't there yet to get hpd in these
situations.

Changes since v1:
 - Add comment explaining the addition of the if
   (!mode_config->poll_running) in intel_hpd_init()
 - Remove unneeded if (!dev->mode_config.poll_enabled) in
   i915_hpd_poll_init_work()
 - Call to drm_helper_hpd_irq_event() after we disable polling
 - Add cancel_work_sync() call to intel_hpd_cancel_work()

Changes since v2:
 - Apparently dev->mode_config.poll_running doesn't actually reflect
   whether or not a poll is currently in progress, and is actually used
   for dynamic module paramter enabling/disabling. So now we instead
   keep track of our own poll_running variable in dev_priv->hotplug
 - Clean i915_hpd_poll_init_work() a little bit

Changes since v3:
 - Remove the now-redundant connector loop in intel_hpd_init(), just
   rely on intel_hpd_poll_enable() for setting connector->polled
   correctly on each connector
 - Get rid of poll_running
 - Don't assign enabled in i915_hpd_poll_init_work before we actually
   lock dev->mode_config.mutex
 - Wrap enabled assignment in i915_hpd_poll_init_work() in READ_ONCE()
   for doc purposes
 - Do the same for dev_priv->hotplug.poll_enabled with WRITE_ONCE in
   intel_hpd_poll_enable()
 - Add some comments about racing not mattering in intel_hpd_poll_enable

Changes since v4:
 - Rename intel_hpd_poll_enable() to intel_hpd_poll_init()
 - Drop the bool argument from intel_hpd_poll_init()
 - Remove redundant calls to intel_hpd_poll_init()
 - Rename poll_enable_work to poll_init_work
 - Add some kerneldoc for intel_hpd_poll_init()
 - Cross-reference intel_hpd_poll_init() in intel_hpd_init()
 - Just copy the loop from intel_hpd_init() in intel_hpd_poll_init()

Changes since v5:
 - Minor kerneldoc nitpicks

Cc: stable@vger.kernel.org
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Lyude <cpaul@redhat.com>
---
 drivers/gpu/drm/i915/i915_drv.c         |  3 ++
 drivers/gpu/drm/i915/i915_drv.h         |  3 ++
 drivers/gpu/drm/i915/intel_drv.h        |  2 +
 drivers/gpu/drm/i915/intel_hotplug.c    | 90 ++++++++++++++++++++++++++++-----
 drivers/gpu/drm/i915/intel_runtime_pm.c |  2 +
 5 files changed, 88 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 3eb47fb..86ff8a7 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1612,6 +1612,9 @@ static int intel_runtime_suspend(struct device *device)
 
 	assert_forcewakes_inactive(dev_priv);
 
+	if (!IS_VALLEYVIEW(dev_priv) || !IS_CHERRYVIEW(dev_priv))
+		intel_hpd_poll_init(dev_priv);
+
 	DRM_DEBUG_KMS("Device suspended\n");
 	return 0;
 }
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 239a3ec..bbcd625 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -283,6 +283,9 @@ struct i915_hotplug {
 	u32 short_port_mask;
 	struct work_struct dig_port_work;
 
+	struct work_struct poll_init_work;
+	bool poll_enabled;
+
 	/*
 	 * if we get a HPD irq from DP and a HPD irq from non-DP
 	 * the non-DP HPD could block the workqueue on a mode config
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index dcbfdde..8af0668 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1385,6 +1385,8 @@ int intel_dsi_dcs_init_backlight_funcs(struct intel_connector *intel_connector);
 
 /* intel_dvo.c */
 void intel_dvo_init(struct drm_device *dev);
+/* intel_hotplug.c */
+void intel_hpd_poll_init(struct drm_i915_private *dev_priv);
 
 
 /* legacy fbdev emulation in intel_fbdev.c */
diff --git a/drivers/gpu/drm/i915/intel_hotplug.c b/drivers/gpu/drm/i915/intel_hotplug.c
index ec3285f..816c761 100644
--- a/drivers/gpu/drm/i915/intel_hotplug.c
+++ b/drivers/gpu/drm/i915/intel_hotplug.c
@@ -452,20 +452,47 @@ void intel_hpd_irq_handler(struct drm_i915_private *dev_priv,
  *
  * This is a separate step from interrupt enabling to simplify the locking rules
  * in the driver load and resume code.
+ *
+ * Also see: intel_hpd_poll_init(), which enables connector polling
  */
 void intel_hpd_init(struct drm_i915_private *dev_priv)
 {
-	struct drm_device *dev = dev_priv->dev;
-	struct drm_mode_config *mode_config = &dev->mode_config;
-	struct drm_connector *connector;
 	int i;
 
 	for_each_hpd_pin(i) {
 		dev_priv->hotplug.stats[i].count = 0;
 		dev_priv->hotplug.stats[i].state = HPD_ENABLED;
 	}
+
+	WRITE_ONCE(dev_priv->hotplug.poll_enabled, false);
+	schedule_work(&dev_priv->hotplug.poll_init_work);
+
+	/*
+	 * Interrupt setup is already guaranteed to be single-threaded, this is
+	 * just to make the assert_spin_locked checks happy.
+	 */
+	spin_lock_irq(&dev_priv->irq_lock);
+	if (dev_priv->display.hpd_irq_setup)
+		dev_priv->display.hpd_irq_setup(dev_priv);
+	spin_unlock_irq(&dev_priv->irq_lock);
+}
+
+void i915_hpd_poll_init_work(struct work_struct *work) {
+	struct drm_i915_private *dev_priv =
+		container_of(work, struct drm_i915_private,
+			     hotplug.poll_init_work);
+	struct drm_device *dev = dev_priv->dev;
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	struct drm_connector *connector;
+	bool enabled;
+
+	mutex_lock(&dev->mode_config.mutex);
+
+	enabled = READ_ONCE(dev_priv->hotplug.poll_enabled);
+
 	list_for_each_entry(connector, &mode_config->connector_list, head) {
-		struct intel_connector *intel_connector = to_intel_connector(connector);
+		struct intel_connector *intel_connector =
+			to_intel_connector(connector);
 		connector->polled = intel_connector->polled;
 
 		/* MST has a dynamic intel_connector->encoder and it's reprobing
@@ -474,24 +501,62 @@ void intel_hpd_init(struct drm_i915_private *dev_priv)
 			continue;
 
 		if (!connector->polled && I915_HAS_HOTPLUG(dev) &&
-		    intel_connector->encoder->hpd_pin > HPD_NONE)
-			connector->polled = DRM_CONNECTOR_POLL_HPD;
+		    intel_connector->encoder->hpd_pin > HPD_NONE) {
+			connector->polled = enabled ?
+				DRM_CONNECTOR_POLL_CONNECT |
+				DRM_CONNECTOR_POLL_DISCONNECT :
+				DRM_CONNECTOR_POLL_HPD;
+		}
 	}
 
+	if (enabled)
+		drm_kms_helper_poll_enable_locked(dev);
+
+	mutex_unlock(&dev->mode_config.mutex);
+
 	/*
-	 * Interrupt setup is already guaranteed to be single-threaded, this is
-	 * just to make the assert_spin_locked checks happy.
+	 * We might have missed any hotplugs that happened while we were
+	 * in the middle of disabling polling
 	 */
-	spin_lock_irq(&dev_priv->irq_lock);
-	if (dev_priv->display.hpd_irq_setup)
-		dev_priv->display.hpd_irq_setup(dev_priv);
-	spin_unlock_irq(&dev_priv->irq_lock);
+	if (!enabled)
+		drm_helper_hpd_irq_event(dev);
+}
+
+/**
+ * intel_hpd_poll_init - enables/disables polling for connectors with hpd
+ * @dev_priv: i915 device instance
+ * @enabled: Whether to enable or disable polling
+ *
+ * This function enables polling for all connectors, regardless of whether or
+ * not they support hotplug detection. Under certain conditions HPD may not be
+ * functional. On most Intel GPUs, this happens when we enter runtime suspend.
+ * On Valleyview and Cherryview systems, this also happens when we shut off all
+ * of the powerwells.
+ *
+ * Since this function can get called in contexts where we're already holding
+ * dev->mode_config.mutex, we do the actual hotplug enabling in a seperate
+ * worker.
+ *
+ * Also see: intel_hpd_init(), which restores hpd handling.
+ */
+void intel_hpd_poll_init(struct drm_i915_private *dev_priv)
+{
+	WRITE_ONCE(dev_priv->hotplug.poll_enabled, true);
+
+	/*
+	 * We might already be holding dev->mode_config.mutex, so do this in a
+	 * seperate worker
+	 * As well, there's no issue if we race here since we always reschedule
+	 * this worker anyway
+	 */
+	schedule_work(&dev_priv->hotplug.poll_init_work);
 }
 
 void intel_hpd_init_work(struct drm_i915_private *dev_priv)
 {
 	INIT_WORK(&dev_priv->hotplug.hotplug_work, i915_hotplug_work_func);
 	INIT_WORK(&dev_priv->hotplug.dig_port_work, i915_digport_work_func);
+	INIT_WORK(&dev_priv->hotplug.poll_init_work, i915_hpd_poll_init_work);
 	INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work,
 			  intel_hpd_irq_storm_reenable_work);
 }
@@ -508,6 +573,7 @@ void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
 
 	cancel_work_sync(&dev_priv->hotplug.dig_port_work);
 	cancel_work_sync(&dev_priv->hotplug.hotplug_work);
+	cancel_work_sync(&dev_priv->hotplug.poll_init_work);
 	cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);
 }
 
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index f88ef76..ada1731 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -1120,6 +1120,8 @@ static void vlv_display_power_well_deinit(struct drm_i915_private *dev_priv)
 	synchronize_irq(dev_priv->dev->irq);
 
 	vlv_power_sequencer_reset(dev_priv);
+
+	intel_hpd_poll_init(dev_priv);
 }
 
 static void vlv_display_power_well_enable(struct drm_i915_private *dev_priv,
-- 
2.5.5