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From ce29728ef6485a367934cc100249c66dd3cde5b6 Mon Sep 17 00:00:00 2001
From: Nicholas Susanto <nicholas.susanto@amd.com>
Date: Fri, 1 Dec 2023 06:25:15 -0700
Subject: [PATCH] drm/amd/display: Fix disable_otg_wa logic
Git-commit: 2ce156482a6fef349d2eba98e5070c412d3af662
Patch-mainline: v6.8-rc1
References: git-fixes CVE-2023-52634 bsc#1222278

[ Upstream commit 2ce156482a6fef349d2eba98e5070c412d3af662 ]

[Why]
When switching to another HDMI mode, we are unnecesarilly
disabling/enabling FIFO causing both HPO and DIG registers to be set at
the same time when only HPO is supposed to be set.

This can lead to a system hang the next time we change refresh rates as
there are cases when we don't disable OTG/FIFO but FIFO is enabled when
it isn't supposed to be.

[How]
Removing the enable/disable FIFO entirely.

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Nicholas Susanto <nicholas.susanto@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 .../gpu/drm/amd/display/dc/clk_mgr/dcn35/dcn35_clk_mgr.c  | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn35/dcn35_clk_mgr.c b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn35/dcn35_clk_mgr.c
index 45ede6440a79..4ef90a3add1c 100644
--- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn35/dcn35_clk_mgr.c
+++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn35/dcn35_clk_mgr.c
@@ -126,21 +126,13 @@ static void dcn35_disable_otg_wa(struct clk_mgr *clk_mgr_base, struct dc_state *
 			continue;
 		if (pipe->stream && (pipe->stream->dpms_off || dc_is_virtual_signal(pipe->stream->signal) ||
 				     !pipe->stream->link_enc)) {
-			struct stream_encoder *stream_enc = pipe->stream_res.stream_enc;
-
 			if (disable) {
-				if (stream_enc && stream_enc->funcs->disable_fifo)
-					pipe->stream_res.stream_enc->funcs->disable_fifo(stream_enc);
-
 				if (pipe->stream_res.tg && pipe->stream_res.tg->funcs->immediate_disable_crtc)
 					pipe->stream_res.tg->funcs->immediate_disable_crtc(pipe->stream_res.tg);
 
 				reset_sync_context_for_pipe(dc, context, i);
 			} else {
 				pipe->stream_res.tg->funcs->enable_crtc(pipe->stream_res.tg);
-
-				if (stream_enc && stream_enc->funcs->enable_fifo)
-					pipe->stream_res.stream_enc->funcs->enable_fifo(stream_enc);
 			}
 		}
 	}
-- 
2.35.3