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 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 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); }