linux-kernel - [PATCH v4 2/3] drm/i915/vlv: Reset the ADPA in vlv_display_power_well

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Message-Id: <1461098444-16370-1-git-send-email-cpaul@redhat.com>
Date:	Tue, 19 Apr 2016 16:40:44 -0400
From:	Lyude <cpaul@...hat.com>
To:	Ville Syrjälä 
	<ville.syrjala@...ux.intel.com>
Cc:	Lyude <cpaul@...hat.com>, stable@...r.kernel.org,
	Daniel Vetter <daniel.vetter@...el.com>,
	Jani Nikula <jani.nikula@...ux.intel.com>,
	David Airlie <airlied@...ux.ie>,
	intel-gfx@...ts.freedesktop.org (open list:INTEL DRM DRIVERS (excluding
	Poulsbo, Moorestow...), dri-devel@...ts.freedesktop.org (open list:INTEL
	DRM DRIVERS (excluding Poulsbo, Moorestow...),
	linux-kernel@...r.kernel.org (open list)))
Subject: [PATCH v4 2/3] drm/i915/vlv: Reset the ADPA in vlv_display_power_well_init()

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@...r.kernel.org
Signed-off-by: Lyude <cpaul@...hat.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@...ux.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 220ca91..54db931 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -707,7 +707,7 @@ 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 e0fcfa1..4e96d5c 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1044,7 +1044,7 @@ 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 80e8bd4..b643533 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -902,6 +902,7 @@ static bool vlv_power_well_enabled(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;
 
 	/*
@@ -935,6 +936,12 @@ 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