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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org,
	stable@vger.kernel.org
Cc: Sung Joon Kim <sungjoon.kim@amd.com>,
	Anthony Koo <anthony.koo@amd.com>,
	Wayne Lin <wayne.lin@amd.com>,
	Daniel Wheeler <daniel.wheeler@amd.com>,
	Alex Deucher <alexander.deucher@amd.com>,
	Sasha Levin <sashal@kernel.org>,
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	sunpeng.li@amd.com,
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	dri-devel@lists.freedesktop.org
Subject: [PATCH AUTOSEL 6.8 42/52] drm/amd/display: Disable seamless boot on 128b/132b encoding
Date: Tue,  7 May 2024 19:07:08 -0400
Message-ID: <20240507230800.392128-42-sashal@kernel.org>
In-Reply-To: <20240507230800.392128-1-sashal@kernel.org>
References: <20240507230800.392128-1-sashal@kernel.org>
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From: Sung Joon Kim <sungjoon.kim@amd.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@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Sung Joon Kim <sungjoon.kim@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.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 3c3d613c5f00e..040b5c2a57586 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
@@ -1804,6 +1804,9 @@ 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