[PATCH 3/4] drm/msm/dp: skip LTTPR init when no LTTPRs are present

[Saurabh Anand]

drm_dp_lttpr_count() returns 0 when no LTTPRs are detected and a
negative value on error. The previous code passed the result directly
to drm_dp_lttpr_init() without checking, which would call into the
LTTPR transparency-mode setup with a zero or negative repeater count.

Add an early return for lttpr_count <= 0 to skip the init entirely
when there are no repeaters in the link, matching the expected usage
of drm_dp_lttpr_init().

Signed-off-by: Saurabh Anand <saurabh.anand at oss.qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 40e19d506a45..1f60c78a463d 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -253,6 +253,10 @@ static int msm_dp_display_lttpr_init(struct msm_dp_display_private *dp, u8 *dpcd
 		return 0;
 
 	lttpr_count = drm_dp_lttpr_count(dp->link->lttpr_common_caps);
+
+	if (lttpr_count <= 0)
+		return 0;
+
 	rc = drm_dp_lttpr_init(dp->aux, lttpr_count);
 	if (rc) {
 		DRM_ERROR("failed to set LTTPRs transparency mode, rc=%d\n", rc);

-- 
2.34.1