From 533a076a85076a24904ac3a2b34cb6e701c5f049 Mon Sep 17 00:00:00 2001
From: Wayne Lin <Wayne.Lin@amd.com>
Date: Thu, 28 Apr 2022 20:49:44 +0800
Subject: drm/dp_mst: Lower down debug info level when receive NAK
Git-commit: 1e6b8d5df017aa7a0cbff4555d1803ea3e8b3d8e
Patch-mainline: v5.19-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

[Why]
It's reasonable that we receive NAK while doing DP_REMOTE_DPCD_READ.
Downstream device might reply NAK with the reason and source should
react accordingly.

e.g.
1. When downstream device can't handle corresponding message in time,
it then replies NAK as reason been set as DEFER.
2. When multi-function branch-sink device doesn't enumerate virtual
DP peer devices for those multi-function down facing ports. Without
virtual DPCD, branch device might reply NAK with reason as BAD_PARAM
indicating this port can't do aux DPCD read.

It's expected result. Not an error.

[How]
Use drm_dbg_kms() to replace drm_err() when receive NAK.

Changes since v1:
* drm_dp_mst_topology.c file path changed. Folder was rename from
 'dp' to 'display'

Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
[fixed some indenting issues]
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220428124944.1683680-1-Wayne.Lin@amd.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/display/drm_dp_mst_topology.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index e2c84b6453bd..67b3b9697da7 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -3557,10 +3557,9 @@ static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
 	if (ret < 0)
 		goto fail_free;
 
-	/* DPCD read should never be NACKed */
 	if (txmsg->reply.reply_type == 1) {
-		drm_err(mgr->dev, "mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n",
-			mstb, port->port_num, offset, size);
+		drm_dbg_kms(mgr->dev, "mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n",
+			    mstb, port->port_num, offset, size);
 		ret = -EIO;
 		goto fail_free;
 	}
-- 
2.38.1