drm/radeon/evergreen+: don't enable HPD interrupts on eDP/LVDS

commit 2e97be7 upstream.

Avoids potential interrupt storms when the display is disabled.

May fix:
https://bugzilla.kernel.org/show_bug.cgi?id=56041

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/gpu/drm/radeon/evergreen.c

@@ -445,6 +445,16 @@ void evergreen_hpd_init(struct radeon_device *rdev)
 
 	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
 		struct radeon_connector *radeon_connector = to_radeon_connector(connector);
+
+		if (connector->connector_type == DRM_MODE_CONNECTOR_eDP ||
+		    connector->connector_type == DRM_MODE_CONNECTOR_LVDS) {
+			/* don't try to enable hpd on eDP or LVDS avoid breaking the
+			 * aux dp channel on imac and help (but not completely fix)
+			 * https://bugzilla.redhat.com/show_bug.cgi?id=726143
+			 * also avoid interrupt storms during dpms.
+			 */
+			continue;
+		}
 		switch (radeon_connector->hpd.hpd) {
 		case RADEON_HPD_1:
 			WREG32(DC_HPD1_CONTROL, tmp);