drm/i915/gen4: Extra CRT hotplug paranoia
Disable the CRT plug interrupt while doing the force cycle, explicitly
clear any CRT interrupt we may have generated, and restore when done.
Should mitigate interrupt storms from hotplug detection.
Signed-off-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index d5c1302..22ff384 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -217,7 +217,8 @@
{
struct drm_device *dev = connector->dev;
struct drm_i915_private *dev_priv = dev->dev_private;
- u32 hotplug_en;
+ u32 hotplug_en, orig, stat;
+ bool ret = false;
int i, tries = 0;
if (HAS_PCH_SPLIT(dev))
@@ -232,8 +233,8 @@
tries = 2;
else
tries = 1;
- hotplug_en = I915_READ(PORT_HOTPLUG_EN);
- hotplug_en &= CRT_FORCE_HOTPLUG_MASK;
+ hotplug_en = orig = I915_READ(PORT_HOTPLUG_EN);
+ hotplug_en &= CRT_HOTPLUG_MASK;
hotplug_en |= CRT_HOTPLUG_FORCE_DETECT;
if (IS_G4X(dev))
@@ -255,11 +256,17 @@
} while (time_after(timeout, jiffies));
}
- if ((I915_READ(PORT_HOTPLUG_STAT) & CRT_HOTPLUG_MONITOR_MASK) !=
- CRT_HOTPLUG_MONITOR_NONE)
- return true;
+ stat = I915_READ(PORT_HOTPLUG_STAT);
+ if ((stat & CRT_HOTPLUG_MONITOR_MASK) != CRT_HOTPLUG_MONITOR_NONE)
+ ret = true;
- return false;
+ /* clear the interrupt we just generated, if any */
+ I915_WRITE(PORT_HOTPLUG_STAT, CRT_HOTPLUG_INT_STATUS);
+
+ /* and put the bits back */
+ I915_WRITE(PORT_HOTPLUG_EN, orig);
+
+ return ret;
}
static bool intel_crt_detect_ddc(struct drm_encoder *encoder)