[PATCH 1/1] UBUNTU: SAUCE: Revert "drm/i915: Fix hotplug irq ack on i965/g4x"

[Kai-Heng Feng]

BugLink: https://bugs.launchpad.net/bugs/1819486

This reverts commit 2f2a7c6570455b1d49161f14ecd1438b3504deab.

Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
---
 drivers/gpu/drm/i915/i915_irq.c | 32 ++------------------------------
 1 file changed, 2 insertions(+), 30 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 38d6d1bfe14e..f6d496c09d3f 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1956,38 +1956,10 @@ static void valleyview_pipestat_irq_handler(struct drm_i915_private *dev_priv,
 
 static u32 i9xx_hpd_irq_ack(struct drm_i915_private *dev_priv)
 {
-	u32 hotplug_status = 0, hotplug_status_mask;
-	int i;
-
-	if (IS_G4X(dev_priv) ||
-	    IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
-		hotplug_status_mask = HOTPLUG_INT_STATUS_G4X |
-			DP_AUX_CHANNEL_MASK_INT_STATUS_G4X;
-	else
-		hotplug_status_mask = HOTPLUG_INT_STATUS_I915;
+	u32 hotplug_status = I915_READ(PORT_HOTPLUG_STAT);
 
-	/*
-	 * We absolutely have to clear all the pending interrupt
-	 * bits in PORT_HOTPLUG_STAT. Otherwise the ISR port
-	 * interrupt bit won't have an edge, and the i965/g4x
-	 * edge triggered IIR will not notice that an interrupt
-	 * is still pending. We can't use PORT_HOTPLUG_EN to
-	 * guarantee the edge as the act of toggling the enable
-	 * bits can itself generate a new hotplug interrupt :(
-	 */
-	for (i = 0; i < 10; i++) {
-		u32 tmp = I915_READ(PORT_HOTPLUG_STAT) & hotplug_status_mask;
-
-		if (tmp == 0)
-			return hotplug_status;
-
-		hotplug_status |= tmp;
+	if (hotplug_status)
 		I915_WRITE(PORT_HOTPLUG_STAT, hotplug_status);
-	}
-
-	WARN_ONCE(1,
-		  "PORT_HOTPLUG_STAT did not clear (0x%08x)\n",
-		  I915_READ(PORT_HOTPLUG_STAT));
 
 	return hotplug_status;
 }
-- 
2.17.1