diff mbox series

[v2,1/2] drm/dp_mst: Revise broadcast msg lct & lcr

Message ID 20210224101521.6713-2-Wayne.Lin@amd.com (mailing list archive)
State New, archived
Headers show
Series Set CLEAR_PAYLOAD_ID_TABLE as broadcast request | expand

Commit Message

Lin, Wayne Feb. 24, 2021, 10:15 a.m. UTC 
[Why & How]
According to DP spec, broadcast message LCT equals to 1 and LCR equals
to 6. Current implementation is incorrect. Fix it.
In addition, revise a bit the hdr->rad handling to include broadcast
case.

Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Cc: stable@vger.kernel.org
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 17dbed0a9800..f11b3f718031 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -2727,10 +2727,15 @@  static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
 	else
 		hdr->broadcast = 0;
 	hdr->path_msg = txmsg->path_msg;
-	hdr->lct = mstb->lct;
-	hdr->lcr = mstb->lct - 1;
-	if (mstb->lct > 1)
-		memcpy(hdr->rad, mstb->rad, mstb->lct / 2);
+	if (hdr->broadcast) {
+		hdr->lct = 1;
+		hdr->lcr = 6;
+	} else {
+		hdr->lct = mstb->lct;
+		hdr->lcr = mstb->lct - 1;
+	}
+
+	memcpy(hdr->rad, mstb->rad, hdr->lct / 2);
 
 	return 0;
 }