From: Wesley Chalmers Date: Wed, 5 May 2021 19:17:48 +0000 (-0400) Subject: drm/amd/display: Improve logic for is_lttpr_present X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=788797c793788415426ef7249ca81c66bbfb9f14;p=linux.git drm/amd/display: Improve logic for is_lttpr_present [WHY] DP specifies that an LTTPR device is only present if PHY_REPEATER_CNT is 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, or 0x01. All other values should be considered no LTTPRs present. [HOW] Function dp_convert_to_count already does this check. Use it to determine if PHY_REPEATER_CNT is a valid LTTPR count. Signed-off-by: Wesley Chalmers Reviewed-by: Jun Lei Acked-by: Anson Jacob Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher --- diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c index c68b49a14f883..7e52bb3047bc8 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c @@ -3699,8 +3699,7 @@ bool dp_retrieve_lttpr_cap(struct dc_link *link) DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV]; /* Attempt to train in LTTPR transparent mode if repeater count exceeds 8. */ - is_lttpr_present = (link->dpcd_caps.lttpr_caps.phy_repeater_cnt > 0 && - link->dpcd_caps.lttpr_caps.phy_repeater_cnt < 0xff && + is_lttpr_present = (dp_convert_to_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt) != 0 && link->dpcd_caps.lttpr_caps.max_lane_count > 0 && link->dpcd_caps.lttpr_caps.max_lane_count <= 4 && link->dpcd_caps.lttpr_caps.revision.raw >= 0x14);