2016-04-18 14:00:42

by Lyude Paul

[permalink] [raw]
Subject: [PATCH v3 2/2] 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 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: [email protected]
Signed-off-by: Lyude <[email protected]>
---
drivers/gpu/drm/i915/intel_runtime_pm.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 80e8bd4..0eae08a 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)
+ encoder->base.funcs->reset(&encoder->base);
+ }
+
i915_redisable_vga_power_on(dev_priv->dev);
}

--
2.5.5