[PATCH] drm/ast: Fix soft lockup

[Jammy Huang]

Avoid infinite-loop in ast_dp_set_on_off().

Signed-off-by: Jammy Huang <jammy_huang at aspeedtech.com>
---
 drivers/gpu/drm/ast/ast_dp.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/ast/ast_dp.c b/drivers/gpu/drm/ast/ast_dp.c
index ebb6d8ebd44e..1e9259416980 100644
--- a/drivers/gpu/drm/ast/ast_dp.c
+++ b/drivers/gpu/drm/ast/ast_dp.c
@@ -180,6 +180,7 @@ void ast_dp_set_on_off(struct drm_device *dev, bool on)
 {
 	struct ast_device *ast = to_ast_device(dev);
 	u8 video_on_off = on;
+	u32 i = 0;
 
 	// Video On/Off
 	ast_set_index_reg_mask(ast, AST_IO_VGACRI, 0xE3, (u8) ~AST_DP_VIDEO_ENABLE, on);
@@ -192,6 +193,8 @@ void ast_dp_set_on_off(struct drm_device *dev, bool on)
 						ASTDP_MIRROR_VIDEO_ENABLE) != video_on_off) {
 			// wait 1 ms
 			mdelay(1);
+			if (++i > 200)
+				break;
 		}
 	}
 }

base-commit: b0546776ad3f332e215cebc0b063ba4351971cca
-- 
2.25.1