On Mon, 19 Apr 2010, avictor.za@xxxxxxxxx wrote:
> hi David,
>
> I'm hoping you can point me in the right direction to get this working.
>
> I have a USB device, which supposedly exposes an Ethernet Gadget
> (RNDIS) interface.
> The device is detected fine and works under Windows, but I just can't
> get it detected on Linux.
>
> The usbnet_probe() in usbnet.c doesn't even get called
>
>
> > modprobe rndis_host
> > dmesg
> [ 81.345662] usbcore: registered new interface driver cdc_ether
> [ 81.365087] usbcore: registered new interface driver rndis_host
> [ 93.620023] usb 1-6: new high speed USB device using ehci_hcd and address 2
> [ 93.852765] usb 1-6: config 1 has 0 interfaces, different from the
> descriptor's value: 1
> [ 93.853384] usb 1-6: configuration #1 chosen from 2 choices
> > cat /debugfs/usb/devices
>
> T: Bus=01 Lev=01 Prnt=01 Port=05 Cnt=01 Dev#= 2 Spd=480 MxCh= 0
> D: Ver= 2.00 Cls=02(comm.) Sub=00 Prot=00 MxPS=64 #Cfgs= 2
> P: Vendor=07a6 ProdID=4610 Rev= 2.18
> S: Manufacturer=Linux 2.6.20-Amazon_SE/dwc_otg_pcd
> S: Product=RNDIS/Ethernet Gadget
> S: SerialNumber=080112111113
> C: #Ifs= 2 Cfg#= 2 Atr=c0 MxPwr=500mA
> I: If#= 0 Alt= 0 #EPs= 1 Cls=02(comm.) Sub=02 Prot=ff Driver=
> E: Ad=83(I) Atr=03(Int.) MxPS= 16 Ivl=32ms
> I: If#= 1 Alt= 0 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=
> E: Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
> E: Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
> C:* #Ifs= 0 Cfg#= 1 Atr=c0 MxPwr=500mA
>
>
> The host is an x86 running 2.6.31.9.
>
> Any suggestions would be much appreciated.
Hah, this is amusing. It looks like you found a bug in the code Linux
uses for choosing the "best" configuration.
Below is a patch to fix the bug; you can test it. For regular kernels,
you should be able to work around the problem by manually telling the
kernel which configuration to use:
echo 2 >/sys/bus/usb/devices/1-6/bConfigurationValue
Of course, for this to work you have to make sure that
CONFIG_USB_NET_RNDIS_HOST is enabled in your kernel.
Alan Stern
Index: usb-2.6/drivers/usb/core/generic.c
===================================================================
--- usb-2.6.orig/drivers/usb/core/generic.c
+++ usb-2.6/drivers/usb/core/generic.c
@@ -120,7 +120,7 @@ int usb_choose_configuration(struct usb_
* than a vendor-specific driver. */
else if (udev->descriptor.bDeviceClass !=
USB_CLASS_VENDOR_SPEC &&
- (!desc || desc->bInterfaceClass !=
+ (desc && desc->bInterfaceClass !=
USB_CLASS_VENDOR_SPEC)) {
best = c;
break;
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