I am still fighting with a Siemens Gigaset M34 USB DECT adapter
(ID 0681:0026) advertizing, among others, four CDC ACM shared
control/data interfaces. The current probe code in cdc-acm.c refuses
to touch these because of the test for
usb_interface_claimed(data_interface) in line 1031. Also, the endpoint
assignments following that test don't look right for the case where
data_interface == control_interface.
Does the following patch look sensible, or am I completely on
the wrong track?
Thanks,
Tilman
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index d50a99f..8d38813 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1027,22 +1027,35 @@ skip_normal_probe:
/* Accept probe requests only for the control interface */
if (intf != control_interface)
return -ENODEV;
-
- if (usb_interface_claimed(data_interface)) { /* valid in this context */
- dev_dbg(&intf->dev,"The data interface isn't available\n");
- return -EBUSY;
- }
-
-
- if (data_interface->cur_altsetting->desc.bNumEndpoints < 2)
- return -EINVAL;
+ /* find endpoints */
epctrl = &control_interface->cur_altsetting->endpoint[0].desc;
- epread = &data_interface->cur_altsetting->endpoint[0].desc;
- epwrite = &data_interface->cur_altsetting->endpoint[1].desc;
-
+ if (data_interface == control_interface) {
+ /* shared interface */
+ if (data_interface->cur_altsetting->desc.bNumEndpoints < 3)
+ return -EINVAL;
+ dev_dbg(&intf->dev, "Shared interface, shifting data EPs.\n");
+ epread = &data_interface->cur_altsetting->endpoint[1].desc;
+ epwrite = &data_interface->cur_altsetting->endpoint[2].desc;
+ } else {
+ /* separate interfaces */
+ if (usb_interface_claimed(data_interface)) {
+ /* valid in this context */
+ dev_dbg(&intf->dev,
+ "The data interface isn't available\n");
+ return -EBUSY;
+ }
+ if (data_interface->cur_altsetting->desc.bNumEndpoints < 2)
+ return -EINVAL;
+ epread = &data_interface->cur_altsetting->endpoint[0].desc;
+ epwrite = &data_interface->cur_altsetting->endpoint[1].desc;
+ }
/* workaround for switched endpoints */
+ if (usb_endpoint_dir_in(epread) == usb_endpoint_dir_in(epwrite)) {
+ err("Bad data endpoint directions.\n");
+ return -EINVAL;
+ }
if (!usb_endpoint_dir_in(epread)) {
/* descriptors are swapped */
struct usb_endpoint_descriptor *t;
--
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