[PATCH 5.4 015/110] staging: vt6656: use NULLFUCTION stack on mac80211

[Greg Kroah-Hartman]

From: Malcolm Priestley <tvboxspy@xxxxxxxxx>

commit d579c43c82f093e63639151625b2139166c730fd upstream.

It appears that the drivers does not go into power save correctly the
NULL data packets are not being transmitted because it not enabled
in mac80211.

The driver needs to capture ieee80211_is_nullfunc headers and
copy the duration_id to it's own duration data header.

Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Malcolm Priestley <tvboxspy@xxxxxxxxx>
Link: https://lore.kernel.org/r/610971ae-555b-a6c3-61b3-444a0c1e35b4@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/staging/vt6656/main_usb.c |    1 +
 drivers/staging/vt6656/rxtx.c     |   14 +++++---------
 2 files changed, 6 insertions(+), 9 deletions(-)

--- a/drivers/staging/vt6656/main_usb.c
+++ b/drivers/staging/vt6656/main_usb.c
@@ -1016,6 +1016,7 @@ vt6656_probe(struct usb_interface *intf,
 	ieee80211_hw_set(priv->hw, RX_INCLUDES_FCS);
 	ieee80211_hw_set(priv->hw, REPORTS_TX_ACK_STATUS);
 	ieee80211_hw_set(priv->hw, SUPPORTS_PS);
+	ieee80211_hw_set(priv->hw, PS_NULLFUNC_STACK);
 
 	priv->hw->max_signal = 100;
 
--- a/drivers/staging/vt6656/rxtx.c
+++ b/drivers/staging/vt6656/rxtx.c
@@ -278,11 +278,9 @@ static u16 vnt_rxtx_datahead_g(struct vn
 			  PK_TYPE_11B, &buf->b);
 
 	/* Get Duration and TimeStamp */
-	if (ieee80211_is_pspoll(hdr->frame_control)) {
-		__le16 dur = cpu_to_le16(priv->current_aid | BIT(14) | BIT(15));
-
-		buf->duration_a = dur;
-		buf->duration_b = dur;
+	if (ieee80211_is_nullfunc(hdr->frame_control)) {
+		buf->duration_a = hdr->duration_id;
+		buf->duration_b = hdr->duration_id;
 	} else {
 		buf->duration_a = vnt_get_duration_le(priv,
 						tx_context->pkt_type, need_ack);
@@ -371,10 +369,8 @@ static u16 vnt_rxtx_datahead_ab(struct v
 			  tx_context->pkt_type, &buf->ab);
 
 	/* Get Duration and TimeStampOff */
-	if (ieee80211_is_pspoll(hdr->frame_control)) {
-		__le16 dur = cpu_to_le16(priv->current_aid | BIT(14) | BIT(15));
-
-		buf->duration = dur;
+	if (ieee80211_is_nullfunc(hdr->frame_control)) {
+		buf->duration = hdr->duration_id;
 	} else {
 		buf->duration = vnt_get_duration_le(priv, tx_context->pkt_type,
 						    need_ack);