From: Lorenzo Colitti <lorenzo@xxxxxxxxxx> [ Upstream commit 4eea21dc67b0c6ba15ae41b1defa113a680a858e ] The u_ether driver has a qmult setting that multiplies the transmit queue length (which by default is 2). The intent is that it should be enabled at high/super speed, but because the code does not explicitly check for USB_SUPER_PLUS, it is disabled at that speed. Fix this by ensuring that the queue multiplier is enabled for any wired link at high speed or above. Using >= for USB_SPEED_* constants seems correct because it is what the gadget_is_xxxspeed functions do. The queue multiplier substantially helps performance at higher speeds. On a direct SuperSpeed Plus link to a Linux laptop, iperf3 single TCP stream: Before (qmult=1): 1.3 Gbps After (qmult=5): 3.2 Gbps Fixes: 04617db7aa68 ("usb: gadget: add SS descriptors to Ethernet gadget") Reviewed-by: Maciej Żenczykowski <maze@xxxxxxxxxx> Signed-off-by: Lorenzo Colitti <lorenzo@xxxxxxxxxx> Signed-off-by: Felipe Balbi <balbi@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/usb/gadget/function/u_ether.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/gadget/function/u_ether.c b/drivers/usb/gadget/function/u_ether.c index 0ef00315ec737..39ebc1b03698b 100644 --- a/drivers/usb/gadget/function/u_ether.c +++ b/drivers/usb/gadget/function/u_ether.c @@ -93,7 +93,7 @@ struct eth_dev { static inline int qlen(struct usb_gadget *gadget, unsigned qmult) { if (gadget_is_dualspeed(gadget) && (gadget->speed == USB_SPEED_HIGH || - gadget->speed == USB_SPEED_SUPER)) + gadget->speed >= USB_SPEED_SUPER)) return qmult * DEFAULT_QLEN; else return DEFAULT_QLEN; -- 2.25.1