This is a note to let you know that I've just added the patch titled usb: gadget: u_ether: remove interrupt throttling to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: usb-gadget-u_ether-remove-interrupt-throttling.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From fd9afd3cbe404998d732be6cc798f749597c5114 Mon Sep 17 00:00:00 2001 From: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx> Date: Tue, 1 Nov 2016 13:20:22 +0200 Subject: usb: gadget: u_ether: remove interrupt throttling MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx> commit fd9afd3cbe404998d732be6cc798f749597c5114 upstream. According to Dave Miller "the networking stack has a hard requirement that all SKBs which are transmitted must have their completion signalled in a fininte amount of time. This is because, until the SKB is freed by the driver, it holds onto socket, netfilter, and other subsystem resources." In summary, this means that using TX IRQ throttling for the networking gadgets is, at least, complex and we should avoid it for the time being. Reported-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Tested-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Suggested-by: David Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/gadget/function/u_ether.c | 8 -------- 1 file changed, 8 deletions(-) --- a/drivers/usb/gadget/function/u_ether.c +++ b/drivers/usb/gadget/function/u_ether.c @@ -594,14 +594,6 @@ static netdev_tx_t eth_start_xmit(struct req->length = length; - /* throttle high/super speed IRQ rate back slightly */ - if (gadget_is_dualspeed(dev->gadget)) - req->no_interrupt = (((dev->gadget->speed == USB_SPEED_HIGH || - dev->gadget->speed == USB_SPEED_SUPER)) && - !list_empty(&dev->tx_reqs)) - ? ((atomic_read(&dev->tx_qlen) % dev->qmult) != 0) - : 0; - retval = usb_ep_queue(in, req, GFP_ATOMIC); switch (retval) { default: Patches currently in stable-queue which might be from felipe.balbi@xxxxxxxxxxxxxxx are queue-4.4/usb-gadget-u_ether-remove-interrupt-throttling.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html