From bd329e1284bc5fa6adaddd2ee9ca15328749a7a6 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Bj=C3=B8rn=20Mork?= Date: Mon, 22 Oct 2012 10:56:38 +0000 Subject: [PATCH] net: cdc_ncm: do not bind to NCM compatible MBIM devices MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The MBIM specification allows a MBIM device to disguise itself as NCM for backwards compatibility, using additional altsettings with different subclass (control) or protocol (data): C:* #Ifs= 2 Cfg#= 1 Atr=80 MxPwr=100mA I: If#= 0 Alt= 0 #EPs= 1 Cls=02(comm.) Sub=0d Prot=00 Driver=cdc_mbim E: Ad=81(I) Atr=03(Int.) MxPS= 64 Ivl=7ms I:* If#= 0 Alt= 1 #EPs= 1 Cls=02(comm.) Sub=0e Prot=00 Driver=cdc_mbim E: Ad=81(I) Atr=03(Int.) MxPS= 64 Ivl=7ms I: If#= 1 Alt= 0 #EPs= 0 Cls=0a(data ) Sub=00 Prot=01 Driver=cdc_mbim I: If#= 1 Alt= 1 #EPs= 2 Cls=0a(data ) Sub=00 Prot=01 Driver=cdc_mbim E: Ad=81(I) Atr=02(Bulk) MxPS= 64 Ivl=0ms E: Ad=02(O) Atr=02(Bulk) MxPS= 64 Ivl=0ms I:* If#= 1 Alt= 2 #EPs= 2 Cls=0a(data ) Sub=00 Prot=02 Driver=cdc_mbim E: Ad=81(I) Atr=02(Bulk) MxPS= 64 Ivl=0ms E: Ad=02(O) Atr=02(Bulk) MxPS= 64 Ivl=0ms If the MBIM driver is enabled then that should have priority for devices providing such a NCM 1.0 backward compatibility mode. Signed-off-by: Bjørn Mork Signed-off-by: Greg Suarez Signed-off-by: David S. Miller --- drivers/net/usb/cdc_ncm.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c index 17b4ba03cb55..0ed03b1ba39a 100644 --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -563,6 +563,33 @@ static int cdc_ncm_bind(struct usbnet *dev, struct usb_interface *intf) { int ret; + /* The MBIM spec defines a NCM compatible default altsetting, + * which we may have matched: + * + * "Functions that implement both NCM 1.0 and MBIM (an + * “NCM/MBIM function”) according to this recommendation + * shall provide two alternate settings for the + * Communication Interface. Alternate setting 0, and the + * associated class and endpoint descriptors, shall be + * constructed according to the rules given for the + * Communication Interface in section 5 of [USBNCM10]. + * Alternate setting 1, and the associated class and + * endpoint descriptors, shall be constructed according to + * the rules given in section 6 (USB Device Model) of this + * specification." + * + * Do not bind to such interfaces, allowing cdc_mbim to handle + * them + */ +#if IS_ENABLED(CONFIG_USB_NET_CDC_MBIM) + 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; +#endif + /* NCM data altsetting is always 1 */ ret = cdc_ncm_bind_common(dev, intf, 1); -- 2.39.5