drm/amd/display: Ignore UHBR13.5 cable ID cap for passive cable max l…

…ink rate

[Why]
Passive DP40 cables were updated in the latest DP spec to support
UHBR13.5 link rate. Current max link rate logic checks against the
cable ID DPCD even for passive cables.

[How]
Ignore UHBR13.5 cable ID DPCD cap in get_max_link_rate logic.

Reviewed-by: Wenjing Liu <wenjing.liu@amd.com>
Acked-by: Zaeem Mohamed <zaeem.mohamed@amd.com>
Signed-off-by: George Shen <george.shen@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c

@@ -2124,7 +2124,8 @@ struct dc_link_settings dp_get_max_link_cap(struct dc_link *link)
 		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)
+		if (!link->dpcd_caps.cable_id.bits.UHBR13_5_CAPABILITY &&
+				link->dpcd_caps.cable_id.bits.CABLE_TYPE >= 2)
 			is_uhbr13_5_supported = false;
 	}