From: "Leo (Sunpeng) Li" <sunpeng.li@amd.com>
Date: Tue, 16 May 2017 09:55:20 -0400
Subject: drm/amd/display: Fix dcn10 cursor set position hang
Git-commit: d3ec0562085918ba889af3d565b4104adcd4947f
Patch-mainline: v4.15-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Calling dcn10_cursor_set_position() before dcn10_cursor_set_attributes()
with invalid (0-value) attributes can cause the ASIC to hang. This fix
checks that address.quadpart is non-zero within set_position before calling
set_attributes.

Signed-off-by: Leo (Sunpeng) Li <sunpeng.li@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/display/dc/dcn10/dcn10_ipp.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_ipp.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_ipp.c
@@ -614,6 +614,16 @@ static void dcn10_cursor_set_position(
 	uint32_t cur_en = pos->enable ? 1 : 0;
 	uint32_t dst_x_offset = (src_x_offset >= 0) ? src_x_offset : 0;
 
+	/*
+	 * Guard aganst cursor_set_position() from being called with invalid
+	 * attributes
+	 *
+	 * TODO: Look at combining cursor_set_position() and
+	 * cursor_set_attributes() into cursor_update()
+	 */
+	if (ippn10->curs_attr.address.quad_part == 0)
+		return;
+
 	dst_x_offset *= param->ref_clk_khz;
 	dst_x_offset /= param->pixel_clk_khz;