From: Ran Shi <[email protected]> why: With DP2.1a expansion we are allowing DP40 cables to do UHBR13.5
how: Assume UHBR10 means UHBR13.5 also for unknown cable type and passive cable type. Reviewed-by: George Shen <[email protected]> Acked-by: Aurabindo Pillai <[email protected]> Signed-off-by: Ran Shi <[email protected]> --- .../display/dc/link/protocols/link_dp_capability.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 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 db87aa7b5c90..3c5334cdb3fb 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 @@ -412,12 +412,18 @@ static enum dc_link_rate get_cable_max_link_rate(struct dc_link *link) { enum dc_link_rate cable_max_link_rate = LINK_RATE_UNKNOWN; - if (link->dpcd_caps.cable_id.bits.UHBR10_20_CAPABILITY & DP_UHBR20) + if (link->dpcd_caps.cable_id.bits.UHBR10_20_CAPABILITY & DP_UHBR20) { cable_max_link_rate = LINK_RATE_UHBR20; - else if (link->dpcd_caps.cable_id.bits.UHBR13_5_CAPABILITY) + } else if (link->dpcd_caps.cable_id.bits.UHBR13_5_CAPABILITY) { cable_max_link_rate = LINK_RATE_UHBR13_5; - else if (link->dpcd_caps.cable_id.bits.UHBR10_20_CAPABILITY & DP_UHBR10) - cable_max_link_rate = LINK_RATE_UHBR10; + } else if (link->dpcd_caps.cable_id.bits.UHBR10_20_CAPABILITY & DP_UHBR10) { + // allow DP40 cables to do UHBR13.5 for passive or unknown cable type + if (link->dpcd_caps.cable_id.bits.CABLE_TYPE < 2) { + cable_max_link_rate = LINK_RATE_UHBR13_5; + } else { + cable_max_link_rate = LINK_RATE_UHBR10; + } + } return cable_max_link_rate; } -- 2.39.2
