linux-kernel - [PATCH AUTOSEL 6.11 64/87] Revert "drm/amd/display: Block UHBR Based On USB-C PD Cable ID"

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Message-ID: <20241124134102.3344326-64-sashal@kernel.org>
Date: Sun, 24 Nov 2024 08:38:42 -0500
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Ausef Yousof <Ausef.Yousof@....com>,
	Charlene Liu <charlene.liu@....com>,
	Zaeem Mohamed <zaeem.mohamed@....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,
	simona@...ll.ch,
	wenjing.liu@....com,
	alex.hung@....com,
	michael.strauss@....com,
	george.shen@....com,
	daniel.sa@....com,
	amd-gfx@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 6.11 64/87] Revert "drm/amd/display: Block UHBR Based On USB-C PD Cable ID"

From: Ausef Yousof <Ausef.Yousof@....com>

[ Upstream commit d7b86a002cf7e1b55ec311c11264f70d079860b9 ]

This reverts commit 4f01a68751194d05280d659a65758c09e4af04d6.

[why & how]
The offending commit caused a lighting issue for Samsung Odyssey G9
monitors when connecting via USB-C. The commit was intended to block certain UHBR rates.

Reviewed-by: Charlene Liu <charlene.liu@....com>
Signed-off-by: Ausef Yousof <Ausef.Yousof@....com>
Signed-off-by: Zaeem Mohamed <zaeem.mohamed@....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    | 22 +++++--------------
 1 file changed, 6 insertions(+), 16 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 ae6d7e3d117e2..60015e94c4aa8 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
@@ -1402,8 +1402,7 @@ static bool get_usbc_cable_id(struct dc_link *link, union dp_cable_id *cable_id)
 
 	if (!link->ctx->dmub_srv ||
 			link->ep_type != DISPLAY_ENDPOINT_PHY ||
-			link->link_enc->features.flags.bits.DP_IS_USB_C == 0 ||
-			link->link_enc->features.flags.bits.IS_DP2_CAPABLE == 0)
+			link->link_enc->features.flags.bits.DP_IS_USB_C == 0)
 		return false;
 
 	memset(&cmd, 0, sizeof(cmd));
@@ -1416,9 +1415,7 @@ static bool get_usbc_cable_id(struct dc_link *link, union dp_cable_id *cable_id)
 		cable_id->raw = cmd.cable_id.data.output_raw;
 		DC_LOG_DC("usbc_cable_id = %d.\n", cable_id->raw);
 	}
-
-	ASSERT(cmd.cable_id.header.ret_status);
-	return true;
+	return cmd.cable_id.header.ret_status == 1;
 }
 
 static void retrieve_cable_id(struct dc_link *link)
@@ -2090,8 +2087,6 @@ struct dc_link_settings dp_get_max_link_cap(struct dc_link *link)
 	/* get max link encoder capability */
 	if (link_enc)
 		link_enc->funcs->get_max_link_cap(link_enc, &max_link_cap);
-	else
-		return max_link_cap;
 
 	/* Lower link settings based on sink's link cap */
 	if (link->reported_link_cap.lane_count < max_link_cap.lane_count)
@@ -2125,15 +2120,10 @@ struct dc_link_settings dp_get_max_link_cap(struct dc_link *link)
 	 */
 	cable_max_link_rate = get_cable_max_link_rate(link);
 
-	if (!link->dc->debug.ignore_cable_id) {
-		if (cable_max_link_rate != LINK_RATE_UNKNOWN)
-			// cable max link rate known
-			max_link_cap.link_rate = MIN(max_link_cap.link_rate, cable_max_link_rate);
-		else if (link_enc->funcs->is_in_alt_mode && link_enc->funcs->is_in_alt_mode(link_enc))
-			// cable max link rate ambiguous, DP alt mode, limit to HBR3
-			max_link_cap.link_rate = MIN(max_link_cap.link_rate, LINK_RATE_HIGH3);
-		//else {}
-			// cable max link rate ambiguous, DP, do nothing
+	if (!link->dc->debug.ignore_cable_id &&
+			cable_max_link_rate != LINK_RATE_UNKNOWN) {
+		if (cable_max_link_rate < max_link_cap.link_rate)
+			max_link_cap.link_rate = cable_max_link_rate;
 
 		if (!link->dpcd_caps.cable_id.bits.UHBR13_5_CAPABILITY &&
 				link->dpcd_caps.cable_id.bits.CABLE_TYPE >= 2)
-- 
2.43.0