linux-kernel - [PATCH AUTOSEL 6.6 119/294] drm/amd/display: Skip checking FRL

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Message-Id: <20250505225634.2688578-119-sashal@kernel.org>
Date: Mon,  5 May 2025 18:53:39 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: George Shen <george.shen@....com>,
	Wenjing Liu <wenjing.liu@....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,
	christian.koenig@....com,
	airlied@...il.com,
	simona@...ll.ch,
	alex.hung@....com,
	michael.strauss@....com,
	roman.li@....com,
	PeiChen.Huang@....com,
	Ausef.Yousof@....com,
	Cruise.Hung@....com,
	amd-gfx@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 6.6 119/294] drm/amd/display: Skip checking FRL_MODE bit for PCON BW determination

From: George Shen <george.shen@....com>

[ Upstream commit 0584bbcf0c53c133081100e4f4c9fe41e598d045 ]

[Why/How]
Certain PCON will clear the FRL_MODE bit despite supporting the link BW
indicated in the other bits.

Thus, skip checking the FRL_MODE bit when interpreting the
hdmi_encoded_link_bw struct.

Reviewed-by: Wenjing Liu <wenjing.liu@....com>
Signed-off-by: George Shen <george.shen@....com>
Signed-off-by: Wayne Lin <wayne.lin@....com>
Tested-by: Daniel Wheeler <daniel.wheeler@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 .../dc/link/protocols/link_dp_capability.c    | 30 +++++++++----------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
index 3d589072fe307..1e621eae9b7da 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
@@ -239,21 +239,21 @@ static uint32_t intersect_frl_link_bw_support(
 {
 	uint32_t supported_bw_in_kbps = max_supported_frl_bw_in_kbps;
 
-	// HDMI_ENCODED_LINK_BW bits are only valid if HDMI Link Configuration bit is 1 (FRL mode)
-	if (hdmi_encoded_link_bw.bits.FRL_MODE) {
-		if (hdmi_encoded_link_bw.bits.BW_48Gbps)
-			supported_bw_in_kbps = 48000000;
-		else if (hdmi_encoded_link_bw.bits.BW_40Gbps)
-			supported_bw_in_kbps = 40000000;
-		else if (hdmi_encoded_link_bw.bits.BW_32Gbps)
-			supported_bw_in_kbps = 32000000;
-		else if (hdmi_encoded_link_bw.bits.BW_24Gbps)
-			supported_bw_in_kbps = 24000000;
-		else if (hdmi_encoded_link_bw.bits.BW_18Gbps)
-			supported_bw_in_kbps = 18000000;
-		else if (hdmi_encoded_link_bw.bits.BW_9Gbps)
-			supported_bw_in_kbps = 9000000;
-	}
+	/* Skip checking FRL_MODE bit, as certain PCON will clear
+	 * it despite supporting the link BW indicated in the other bits.
+	 */
+	if (hdmi_encoded_link_bw.bits.BW_48Gbps)
+		supported_bw_in_kbps = 48000000;
+	else if (hdmi_encoded_link_bw.bits.BW_40Gbps)
+		supported_bw_in_kbps = 40000000;
+	else if (hdmi_encoded_link_bw.bits.BW_32Gbps)
+		supported_bw_in_kbps = 32000000;
+	else if (hdmi_encoded_link_bw.bits.BW_24Gbps)
+		supported_bw_in_kbps = 24000000;
+	else if (hdmi_encoded_link_bw.bits.BW_18Gbps)
+		supported_bw_in_kbps = 18000000;
+	else if (hdmi_encoded_link_bw.bits.BW_9Gbps)
+		supported_bw_in_kbps = 9000000;
 
 	return supported_bw_in_kbps;
 }
-- 
2.39.5