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@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>
[danvet: Rebase over dev_priv/drm_device embedding.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index 9cd88293c960..d172930ac1e7 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -717,7 +717,7 @@ 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 = to_i915(dev);