linux-kernel - [PATCH AUTOSEL 6.6 34/43] drm/amd/display: Disable seamless boot on 128b/132b encoding

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Message-ID: <20240507231033.393285-34-sashal@kernel.org>
Date: Tue,  7 May 2024 19:09:55 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Sung Joon Kim <sungjoon.kim@....com>,
	Anthony Koo <anthony.koo@....com>,
	Wayne Lin <wayne.lin@....com>,
	Daniel Wheeler <daniel.wheeler@....com>,
	Alex Deucher <alexander.deucher@....com>,
	Sasha Levin <sashal@...nel.org>,
	harry.wentland@....com,
	sunpeng.li@....com,
	Rodrigo.Siqueira@....com,
	christian.koenig@....com,
	Xinhui.Pan@....com,
	airlied@...il.com,
	daniel@...ll.ch,
	alvin.lee2@....com,
	jun.lei@....com,
	wenjing.liu@....com,
	aric.cyr@....com,
	dillon.varone@....com,
	chiawen.huang@....com,
	amd-gfx@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 6.6 34/43] drm/amd/display: Disable seamless boot on 128b/132b encoding

From: Sung Joon Kim <sungjoon.kim@....com>

[ Upstream commit 6f0c228ed9184287031a66b46a79e5a3d2e73a86 ]

[why]
preOS will not support display mode programming and link training
for UHBR rates.

[how]
If we detect a sink that's UHBR capable, disable seamless boot

Reviewed-by: Anthony Koo <anthony.koo@....com>
Acked-by: Wayne Lin <wayne.lin@....com>
Signed-off-by: Sung Joon Kim <sungjoon.kim@....com>
Tested-by: Daniel Wheeler <daniel.wheeler@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/amd/display/dc/core/dc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c
index 46b10ff8f6d41..72db370e2f21f 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
@@ -1710,6 +1710,9 @@ bool dc_validate_boot_timing(const struct dc *dc,
 		return false;
 	}
 
+	if (link->dpcd_caps.channel_coding_cap.bits.DP_128b_132b_SUPPORTED)
+		return false;
+
 	if (dc->link_srv->edp_is_ilr_optimization_required(link, crtc_timing)) {
 		DC_LOG_EVENT_LINK_TRAINING("Seamless boot disabled to optimize eDP link rate\n");
 		return false;
-- 
2.43.0