mt76: mt7921: consider the invalid value for to_rssi

It is possible the RCPI from the certain antenna is an invalid value,
especially packets are receiving while the system is frequently entering
deep sleep mode, so consider calculating RSSI with the reasonable upper
bound to avoid report the wrong value to the mac80211 layer.

Fixes: 163f4d22c118 ("mt76: mt7921: add MAC support")
Reviewed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
index 31741da140996f4eea855f76766a2633198a9dae..96a6c0aabe06cc6b46be62c6d44c797ec02a0c4e 100644 (file)
--- a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
@@ -461,16 +461,19 @@ int mt7921_mac_fill_rx(struct mt7921_dev *dev, struct sk_buff *skb)
                status->chain_signal[1] = to_rssi(MT_PRXV_RCPI1, v1);
                status->chain_signal[2] = to_rssi(MT_PRXV_RCPI2, v1);
                status->chain_signal[3] = to_rssi(MT_PRXV_RCPI3, v1);
-               status->signal = status->chain_signal[0];
-
-               for (i = 1; i < hweight8(mphy->antenna_mask); i++) {
-                       if (!(status->chains & BIT(i)))
+               status->signal = -128;
+               for (i = 0; i < hweight8(mphy->antenna_mask); i++) {
+                       if (!(status->chains & BIT(i)) ||
+                           status->chain_signal[i] >= 0)
                                continue;
 
                        status->signal = max(status->signal,
                                             status->chain_signal[i]);
                }
 
+               if (status->signal == -128)
+                       status->flag |= RX_FLAG_NO_SIGNAL_VAL;
+
                stbc = FIELD_GET(MT_PRXV_STBC, v0);
                gi = FIELD_GET(MT_PRXV_SGI, v0);
                cck = false;