Revert "USBNET: ax88179_178a: enable tso if usb host supports sg dma"

This reverts commit 9912f321f625e5daca91292c566d4c698865508b.

This commit, together with commit 21a7c3dfabc2334e9f4d7a1665e6fbb4d215e31e
"xhci 1.0: Limit arbitrarily-aligned scatter gather." were
origially added to get xHCI 1.0 hosts and usb ethernet ax88179_178a devices
working together with scatter gather. xHCI 1.0 hosts pose some requirement on how transfer
buffers are aligned, setting this requirement for 1.0 hosts caused USB 3.0 mass
storage devices to fail more frequently.

USB 3.0 mass storage devices used to work before 3.14-rc1.  Theoretically,
the TD fragment rules could have caused an occasional disk glitch.
Now the devices *will* fail, instead of theoretically failing.
>From a user perspective, this looks like a regression; the USB device obviously
fails on 3.14-rc1, and may sometimes silently fail on prior kernels.

The proper soluition is to implement the TD fragment rules for xHCI 1.0 hosts,
but for now, revert this patch until scatter gather can be properly supported.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/usb/ax88179_178a.c b/drivers/net/usb/ax88179_178a.c
index 955df81a43589bc30857b56db94f94886ce9cc30..42085e622be68f8edd75067f2a3994b4972169bf 100644 (file)
--- a/drivers/net/usb/ax88179_178a.c
+++ b/drivers/net/usb/ax88179_178a.c
@@ -1029,20 +1029,12 @@ static int ax88179_bind(struct usbnet *dev, struct usb_interface *intf)
        dev->mii.phy_id = 0x03;
        dev->mii.supports_gmii = 1;
 
-       if (usb_device_no_sg_constraint(dev->udev))
-               dev->can_dma_sg = 1;
-
        dev->net->features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
                              NETIF_F_RXCSUM;
 
        dev->net->hw_features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
                                 NETIF_F_RXCSUM;
 
-       if (dev->can_dma_sg) {
-               dev->net->features |= NETIF_F_SG | NETIF_F_TSO;
-               dev->net->hw_features |= NETIF_F_SG | NETIF_F_TSO;
-       }
-
        /* Enable checksum offload */
        *tmp = AX_RXCOE_IP | AX_RXCOE_TCP | AX_RXCOE_UDP |
               AX_RXCOE_TCPV6 | AX_RXCOE_UDPV6;