drm/amd/display: Fix preferred link rate for NUTMEG

When there is a preferred link rate setting, it needs to be
applied to both the current and initial link rate.
This was regressed by a "coding style" fix, which caused
the current link rate to not respect the preferred value.

This commit restores the functionality of NUTMEG,
the DP bridge encoder found on old APUs such as Kaveri.

Fixes: a62346043a89 ("drm/amd/display: Fix coding style issue")
Closes: https://gitlab.freedesktop.org/drm/amd/-/work_items/5465
Cc: Chuanyu Tseng <Chuanyu.Tseng@amd.com>
Reviewed-by: Fangzhi Zuo <Jerry.Zuo@amd.com>
Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit e78b0a367f8690b682029d90e75308dc84ed51de)
Cc: stable@vger.kernel.org

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 47abb40667092cf1c609723e72c6f2de06402257..4079f128bade56d34a7a17621a21eef72796d03b 100644 (file)
--- 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
@@ -750,8 +750,10 @@ static bool decide_dp_link_settings(struct dc_link *link, struct dc_link_setting
        if (req_bw > dp_link_bandwidth_kbps(link, &link->verified_link_cap))
                return false;
 
-       if (link->preferred_link_setting.link_rate != LINK_RATE_UNKNOWN)
+       if (link->preferred_link_setting.link_rate != LINK_RATE_UNKNOWN) {
                initial_link_setting.link_rate = link->preferred_link_setting.link_rate;
+               current_link_setting.link_rate = link->preferred_link_setting.link_rate;
+       }
 
        /* search for the minimum link setting that:
         * 1. is supported according to the link training result