From ef41eb0a88c461457868669b6506d7eebe3d56d2 Mon Sep 17 00:00:00 2001
From: Sean Paul <seanpaul@chromium.org>
Date: Thu, 13 Feb 2020 16:15:20 -0500
Subject: drm/dp_mst: Remove single tx msg restriction.
Git-commit: 6bb0942e8f46863a745489cce27efe5be2a3885e
Patch-mainline: v5.8-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

Now that we can support multiple simultaneous replies, remove the
restrictions placed on sending new tx msgs.

This patch essentially just reverts commit
  5a64967a2f3b ("drm/dp_mst: Have DP_Tx send one msg at a time")
now that the problem is solved in a different way.

Cc: Wayne Lin <Wayne.Lin@amd.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Wayne Lin <waynelin@amd.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200213211523.156998-4-sean@poorly.run
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 14 ++------------
 include/drm/drm_dp_mst_helper.h       |  5 -----
 2 files changed, 2 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 5c7325434403..f46d22d436c2 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1205,8 +1205,6 @@ static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
 		    txmsg->state == DRM_DP_SIDEBAND_TX_SENT) {
 			mstb->tx_slots[txmsg->seqno] = NULL;
 		}
-		mgr->is_waiting_for_dwn_reply = false;
-
 	}
 out:
 	if (unlikely(ret == -EIO) && drm_debug_enabled(DRM_UT_DP)) {
@@ -1216,7 +1214,6 @@ static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
 	}
 	mutex_unlock(&mgr->qlock);
 
-	drm_dp_mst_kick_tx(mgr);
 	return ret;
 }
 
@@ -2792,11 +2789,9 @@ static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
 	ret = process_single_tx_qlock(mgr, txmsg, false);
 	if (ret == 1) {
 		/* txmsg is sent it should be in the slots now */
-		mgr->is_waiting_for_dwn_reply = true;
 		list_del(&txmsg->next);
 	} else if (ret) {
 		DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
-		mgr->is_waiting_for_dwn_reply = false;
 		list_del(&txmsg->next);
 		if (txmsg->seqno != -1)
 			txmsg->dst->tx_slots[txmsg->seqno] = NULL;
@@ -2836,8 +2831,7 @@ static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
 		drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
 	}
 
-	if (list_is_singular(&mgr->tx_msg_downq) &&
-	    !mgr->is_waiting_for_dwn_reply)
+	if (list_is_singular(&mgr->tx_msg_downq))
 		process_single_down_tx_qlock(mgr);
 	mutex_unlock(&mgr->qlock);
 }
@@ -3833,7 +3827,6 @@ static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
 	mutex_lock(&mgr->qlock);
 	txmsg->state = DRM_DP_SIDEBAND_TX_RX;
 	mstb->tx_slots[seqno] = NULL;
-	mgr->is_waiting_for_dwn_reply = false;
 	mutex_unlock(&mgr->qlock);
 
 	wake_up_all(&mgr->tx_waitq);
@@ -3841,9 +3834,6 @@ static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
 	return 0;
 
 out_clear_reply:
-	mutex_lock(&mgr->qlock);
-	mgr->is_waiting_for_dwn_reply = false;
-	mutex_unlock(&mgr->qlock);
 	if (msg)
 		memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
 out:
@@ -4702,7 +4692,7 @@ static void drm_dp_tx_work(struct work_struct *work)
 	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
 
 	mutex_lock(&mgr->qlock);
-	if (!list_empty(&mgr->tx_msg_downq) && !mgr->is_waiting_for_dwn_reply)
+	if (!list_empty(&mgr->tx_msg_downq))
 		process_single_down_tx_qlock(mgr);
 	mutex_unlock(&mgr->qlock);
 }
diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
index 33db34a88d9d..a2a5a0fe9470 100644
--- a/include/drm/drm_dp_mst_helper.h
+++ b/include/drm/drm_dp_mst_helper.h
@@ -590,11 +590,6 @@ struct drm_dp_mst_topology_mgr {
 	 */
 	bool payload_id_table_cleared : 1;
 
-	/**
-	 * @is_waiting_for_dwn_reply: whether we're waiting for a down reply.
-	 */
-	bool is_waiting_for_dwn_reply : 1;
-
 	/**
 	 * @mst_primary: Pointer to the primary/first branch device.
 	 */
-- 
2.28.0