[PATCH mt76-next 25/25] wifi: mt76: mt7996: keep a unicast management frame on its MLO link

[Felix Fietkau <nbd@nbd.name>]

mt7996_mac_write_txwi_80211() sets MT_TXD5_FL for an MLD interface only
on multicast, EAPOL and 4-address null frames. A unicast management
frame to an MLD peer goes out on a link that the hardware picks among
the links of the peer, not on the link of its TXD. ML reconfiguration
depends on that link: mac80211 removes a link before it sends the Link
Reconfiguration Request, so that the request leaves on a remaining
link, and the AP MLD sends the Response on the link where the request
was received. With hardware link selection, the request leaves on the
removed link, or the AP sends the Response there. The station then
drops the Response, and the link removal ends with a disconnection.

Set MT_TXD5_FL for unicast management frames to a station of an MLD
interface, so that they keep the link that mac80211 or the driver
selected.

Fixes: f0b0b239b8f3 ("wifi: mt76: mt7996: rework mt7996_mac_write_txwi() for MLO support")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 drivers/net/wireless/mediatek/mt76/mt7996/mac.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
index a92536180dbe..03670293a78f 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
@@ -851,7 +851,8 @@ mt7996_mac_write_txwi_80211(struct mt7996_dev *dev, __le32 *txwi,
 	}
 
 	if (vif && ieee80211_vif_is_mld(vif) &&
-	    (multicast || unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE))))
+	    (multicast || unlikely(skb->protocol == cpu_to_be16(ETH_P_PAE)) ||
+	     (ieee80211_is_mgmt(fc) && wcid->sta)))
 		txwi[5] |= cpu_to_le32(MT_TXD5_FL);
 
 	if (ieee80211_is_nullfunc(fc) && ieee80211_has_a4(fc) &&
-- 
2.47.3