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authorLuka Gejak <luka.gejak@linux.dev>2026-05-18 16:23:10 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2026-07-04 13:43:33 +0200
commit81e2d4508b35c6b0d42291b055b85e5889a3f0ba (patch)
tree7d35f29f039bc6e059c5e192d84a06231376e2d5
parent9a6e57ffe49e30adbc32bc728cc1f90fad8589e1 (diff)
downloadlinux-stable-81e2d4508b35c6b0d42291b055b85e5889a3f0ba.tar.gz
linux-stable-81e2d4508b35c6b0d42291b055b85e5889a3f0ba.zip
wifi: rtw88: increase TX report timeout to fix race condition
commit c80788f7c5aed8d420366b821f867a8a353d83a5 upstream. The driver expects the firmware to report TX status within 500ms. However, a timeout can be triggered when the hardware performs background scans while under TX load. During these scans, the firmware stays off-channel for periods exceeding 500ms, delaying the delivery of TX reports back to the driver. When this occurs, the purge timer fires prematurely and drops the tracking skbs from the queue. This results in the host stack interpreting the missing status as packet loss, leading to TCP window collapse. In testing with iperf3, this causes throughput to drop from ~90 Mbps to near-zero for approximately 2 seconds until the connection recovers. Increase RTW_TX_PROBE_TIMEOUT to 2500ms for RTL8723DU. This duration is sufficient to accommodate off-channel dwell time during full background scans, ensuring the purge timer only trips during genuine firmware lockups and preventing unnecessary TCP retransmission cycles. Fixes: a82dfd33d123 ("wifi: rtw88: Add common USB chip support") Cc: stable@vger.kernel.org Acked-by: Ping-Ke Shih <pkshih@realtek.com> Tested-by: Luka Gejak <luka.gejak@linux.dev> Signed-off-by: Luka Gejak <luka.gejak@linux.dev> Signed-off-by: Ping-Ke Shih <pkshih@realtek.com> Link: https://patch.msgid.link/20260518142311.10328-1-luka.gejak@linux.dev Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/net/wireless/realtek/rtw88/tx.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/net/wireless/realtek/rtw88/tx.c b/drivers/net/wireless/realtek/rtw88/tx.c
index dae7ca148865..2e66140c6482 100644
--- a/drivers/net/wireless/realtek/rtw88/tx.c
+++ b/drivers/net/wireless/realtek/rtw88/tx.c
@@ -191,6 +191,7 @@ void rtw_tx_report_purge_timer(struct timer_list *t)
void rtw_tx_report_enqueue(struct rtw_dev *rtwdev, struct sk_buff *skb, u8 sn)
{
struct rtw_tx_report *tx_report = &rtwdev->tx_report;
+ unsigned long timeout = RTW_TX_PROBE_TIMEOUT;
unsigned long flags;
u8 *drv_data;
@@ -202,7 +203,11 @@ void rtw_tx_report_enqueue(struct rtw_dev *rtwdev, struct sk_buff *skb, u8 sn)
__skb_queue_tail(&tx_report->queue, skb);
spin_unlock_irqrestore(&tx_report->q_lock, flags);
- mod_timer(&tx_report->purge_timer, jiffies + RTW_TX_PROBE_TIMEOUT);
+ if (rtwdev->chip->id == RTW_CHIP_TYPE_8723D &&
+ rtwdev->hci.type == RTW_HCI_TYPE_USB)
+ timeout = msecs_to_jiffies(2500);
+
+ mod_timer(&tx_report->purge_timer, jiffies + timeout);
}
EXPORT_SYMBOL(rtw_tx_report_enqueue);