From 8d33ee7534d7d8c0ee9f0aa5aad2fa4522463671 Mon Sep 17 00:00:00 2001 From: Bjørn Mork Date: Wed, 13 Feb 2013 12:09:52 +0000 Subject: net: cdc_ncm: fix probing of devices with multiple control interface altsettings MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit f350ca03703133c94fe742f6fa6ff0fd8f5a9a09 ] commit bd329e1 ("net: cdc_ncm: do not bind to NCM compatible MBIM devices") added a test for a CDC MBIM altsetting, implementing the cdc_ncm part of MBIM backward compatibility support. This intentionally made the driver behave differently for CDC NCM devices with 2 alternate settings for the Communication interface, depending on whether or not CONFIG_USB_NET_CDC_MBIM was enabled. This is correct iff alternate setting #1 really *is* a MBIM setting. If not, then NCM probing will use a different altsetting than before, possibly causing probing failures depending on CONFIG_USB_NET_CDC_MBIM. Fix by setting the altsetting back to default after the test, restoring the previous behaviour for non MBIM devices. This bug causes probing of Huawei E3276 devices to fail when the MBIM driver is enabled, because these devices have a second alternate setting with no CDC functional descriptors. Reported-and-tested-by: Jonathan A. Cc: Greg Suarez Cc: Alexey Orishko Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/usb/cdc_ncm.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c index 00d3b2d3782..6d25439e2c1 100644 --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -576,9 +576,14 @@ static int cdc_ncm_bind(struct usbnet *dev, struct usb_interface *intf) if ((intf->num_altsetting == 2) && !usb_set_interface(dev->udev, intf->cur_altsetting->desc.bInterfaceNumber, - CDC_NCM_COMM_ALTSETTING_MBIM) && - cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting)) - return -ENODEV; + CDC_NCM_COMM_ALTSETTING_MBIM)) { + if (cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting)) + return -ENODEV; + else + usb_set_interface(dev->udev, + intf->cur_altsetting->desc.bInterfaceNumber, + CDC_NCM_COMM_ALTSETTING_NCM); + } #endif /* NCM data altsetting is always 1 */ -- cgit v1.2.3-18-g5258