drm/msm/dp: Fix support of LTTPR initialization

Initialize LTTPR before msm_dp_panel_read_sink_caps, as DPTX shall
(re)read DPRX caps after LTTPR detection, as required by DP 2.1a,
Section 3.6.7.6.1.

Fixes: 72d0af4accd9 ("drm/msm/dp: Add support for LTTPR handling")
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Aleksandrs Vinarskis <alex.vinarskis@gmail.com>
Tested-by: Jessica Zhang <quic_jesszhan@quicinc.com> # SA8775P
Tested-by: Johan Hovold <johan+linaro@kernel.org>
Tested-by: Rob Clark <robdclark@gmail.com>
Patchwork: https://patchwork.freedesktop.org/patch/652301/
Link: https://lore.kernel.org/r/20250507230113.14270-2-alex.vinarskis@gmail.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index ece184d20c0f8bffa3c2a48216015185d6cbc99e..c39c1669c74c0c6a1bcdee05cda1cc26b3fa7e7d 100644 (file)
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -360,12 +360,12 @@ static int msm_dp_display_send_hpd_notification(struct msm_dp_display_private *d
        return 0;
 }
 
-static void msm_dp_display_lttpr_init(struct msm_dp_display_private *dp)
+static void msm_dp_display_lttpr_init(struct msm_dp_display_private *dp, u8 *dpcd)
 {
        u8 lttpr_caps[DP_LTTPR_COMMON_CAP_SIZE];
        int rc;
 
-       if (drm_dp_read_lttpr_common_caps(dp->aux, dp->panel->dpcd, lttpr_caps))
+       if (drm_dp_read_lttpr_common_caps(dp->aux, dpcd, lttpr_caps))
                return;
 
        rc = drm_dp_lttpr_init(dp->aux, drm_dp_lttpr_count(lttpr_caps));
@@ -378,12 +378,17 @@ static int msm_dp_display_process_hpd_high(struct msm_dp_display_private *dp)
        struct drm_connector *connector = dp->msm_dp_display.connector;
        const struct drm_display_info *info = &connector->display_info;
        int rc = 0;
+       u8 dpcd[DP_RECEIVER_CAP_SIZE];
 
-       rc = msm_dp_panel_read_sink_caps(dp->panel, connector);
+       rc = drm_dp_read_dpcd_caps(dp->aux, dpcd);
        if (rc)
                goto end;
 
-       msm_dp_display_lttpr_init(dp);
+       msm_dp_display_lttpr_init(dp, dpcd);
+
+       rc = msm_dp_panel_read_sink_caps(dp->panel, connector);
+       if (rc)
+               goto end;
 
        msm_dp_link_process_request(dp->link);