[PATCH net 4/4] lan78xx: throttle tx path per usb speed
From: <Woojung.Huh@microchip.com>
Date: 2016-01-25 23:04:20
Subsystem:
networking drivers, the rest, usb lan78xx ethernet driver, usb networking drivers · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Thangaraj Samynathan
Throttle TX path when slower than SUPER SPEED USB to avoid choking CPU. Signed-off-by: Woojung Huh <woojung.huh@microchip.com> --- drivers/net/usb/lan78xx.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 9b95333..e0cbc5a 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c@@ -2264,7 +2264,9 @@ netdev_tx_t lan78xx_start_xmit(struct sk_buff *skb, struct net_device *net) if (skb2) { skb_queue_tail(&dev->txq_pend, skb2); - if (skb_queue_len(&dev->txq_pend) > 10) + /* throttle TX patch at slower than SUPER SPEED USB */ + if ((dev->udev->speed < USB_SPEED_SUPER) && + (skb_queue_len(&dev->txq_pend) > 10)) netif_stop_queue(net); } else { netif_dbg(dev, tx_err, dev->net,
--
2.1.4