[PATCH] Revert "drm/amd/display: revert wait in pipelock"

[Alex Deucher]

This reverts commit 617089d5837a3aa4167a9c4afb34929e0d52805d.

This causes hangs in some games.

Bug: https://bugzilla.kernel.org/show_bug.cgi?id=205169
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=112266
Bug: https://bugzilla.kernel.org/show_bug.cgi?id=205169
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
index 0046a099c9e9..9b4488ef27d1 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
@@ -1033,6 +1033,17 @@ void dcn20_pipe_control_lock(
 	if (pipe->plane_state != NULL)
 		flip_immediate = pipe->plane_state->flip_immediate;
 
+	if (flip_immediate && lock) {
+		while (pipe->plane_res.hubp->funcs->hubp_is_flip_pending(pipe->plane_res.hubp))	{
+			udelay(1);
+		}
+
+		if (pipe->bottom_pipe != NULL)
+			while (pipe->bottom_pipe->plane_res.hubp->funcs->hubp_is_flip_pending(pipe->bottom_pipe->plane_res.hubp))	{
+				udelay(1);
+			}
+	}
+
 	/* In flip immediate and pipe splitting case, we need to use GSL
 	 * for synchronization. Only do setup on locking and on flip type change.
 	 */
-- 
2.23.0