[PATCH mt76-next 24/25] wifi: mt76: mt7996: send no MLD_SETUP when station links only go away

[Felix Fietkau <nbd@nbd.name>]

Since links added after association are brought up in
mt7996_mac_sta_links_sync(), the remaining links of an MLO station also
get an MLD_SETUP when links are only removed, with a link list that no
longer holds the removed links. After that MLD_SETUP, the remaining
links pass no traffic in either direction, although TX completes
without failures. Traffic only resumes once a link is added again.

Send the MLD_SETUP to the other links only when a link joins. The
MediaTek driver also sends no firmware command when a link station
goes, and tears down all links with STA_REC_MLD_OFF at disassociation.
This also applies to the restore after a failed link add.

Fixes: 1aef01d3cbbe ("wifi: mt76: mt7996: bring up station links added after association")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 drivers/net/wireless/mediatek/mt76/mt7996/main.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/main.c b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
index 82143ade1cc0..5df5354beb50 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
@@ -1864,7 +1864,8 @@ mt7996_mac_sta_links_sync(struct mt7996_dev *dev, struct ieee80211_vif *vif,
 		mt7996_mac_sta_link_ps_leave(dev, link, msta_link);
 	}
 
-	updated = sta->mlo ? links & ~updated : 0;
+	/* a link list without a removed link stalls the remaining links */
+	updated = sta->mlo && joined ? links & ~updated : 0;
 	for_each_set_bit(link_id, &updated, IEEE80211_MLD_MAX_NUM_LINKS) {
 		struct mt7996_sta_link *msta_link;
 		struct mt7996_vif_link *link;
-- 
2.47.3