3 files changed, 24 insertions, 13 deletions

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 5daa991cb287..f5b0d8306d83 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -39,7 +39,7 @@
 			ret__ = -ETIMEDOUT;				\
 			break;						\
 		}							\
-		if (W && !in_dbg_master()) msleep(W);			\
+		if (W && !(in_atomic() || in_dbg_master())) msleep(W);	\
 	}								\
 	ret__;								\
 })
diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
index 82d04c5899d2..d3b903bce7c5 100644
--- a/drivers/gpu/drm/i915/intel_i2c.c
+++ b/drivers/gpu/drm/i915/intel_i2c.c
@@ -259,7 +259,7 @@ gmbus_xfer(struct i2c_adapter *adapter,
 				if (wait_for(I915_READ(GMBUS2 + reg_offset) & (GMBUS_SATOER | GMBUS_HW_RDY), 50))
 					goto timeout;
 				if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)
-					return 0;
+					goto clear_err;
 
 				val = I915_READ(GMBUS3 + reg_offset);
 				do {
@@ -287,7 +287,7 @@ gmbus_xfer(struct i2c_adapter *adapter,
 				if (wait_for(I915_READ(GMBUS2 + reg_offset) & (GMBUS_SATOER | GMBUS_HW_RDY), 50))
 					goto timeout;
 				if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)
-					return 0;
+					goto clear_err;
 
 				val = loop = 0;
 				do {
@@ -302,14 +302,31 @@ gmbus_xfer(struct i2c_adapter *adapter,
 		if (i + 1 < num && wait_for(I915_READ(GMBUS2 + reg_offset) & (GMBUS_SATOER | GMBUS_HW_WAIT_PHASE), 50))
 			goto timeout;
 		if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)
-			return 0;
+			goto clear_err;
 	}
 
-	return num;
+	goto done;
+
+clear_err:
+	/* Toggle the Software Clear Interrupt bit. This has the effect
+	 * of resetting the GMBUS controller and so clearing the
+	 * BUS_ERROR raised by the slave's NAK.
+	 */
+	I915_WRITE(GMBUS1 + reg_offset, GMBUS_SW_CLR_INT);
+	I915_WRITE(GMBUS1 + reg_offset, 0);
+
+done:
+	/* Mark the GMBUS interface as disabled. We will re-enable it at the
+	 * start of the next xfer, till then let it sleep.
+	 */
+	I915_WRITE(GMBUS0 + reg_offset, 0);
+	return i;
 
 timeout:
 	DRM_INFO("GMBUS timed out, falling back to bit banging on pin %d [%s]\n",
 		 bus->reg0 & 0xff, bus->adapter.name);
+	I915_WRITE(GMBUS0 + reg_offset, 0);
+
 	/* Hardware may not support GMBUS over these pins? Try GPIO bitbanging instead. */
 	bus->force_bit = intel_gpio_create(dev_priv, bus->reg0 & 0xff);
 	if (!bus->force_bit)
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 1a311ad01116..86cd30bcb619 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -473,19 +473,13 @@ static enum drm_connector_status
 intel_lvds_detect(struct drm_connector *connector, bool force)
 {
 	struct drm_device *dev = connector->dev;
-	enum drm_connector_status status = connector_status_connected;
+	enum drm_connector_status status;
 
 	status = intel_panel_detect(dev);
 	if (status != connector_status_unknown)
 		return status;
 
-	/* ACPI lid methods were generally unreliable in this generation, so
-	 * don't even bother.
-	 */
-	if (IS_GEN2(dev) || IS_GEN3(dev))
-		return connector_status_connected;
-
-	return status;
+	return connector_status_connected;
 }
 
 /**