USB: cdc-acm: fix incorrect throtteling, make set_control optional

this is Joris' fixes reshuffelled and features renamed as David requested.

- acm_set_control is not mandatory, honour that
- throtteling is reset upon open
- throtteling is read consistently when processing input data

Signed-off-by: Joris van Rantwijk <jorispubl@xs4all.nl>
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/usb/cdc.h b/include/linux/usb/cdc.h
index ba617c372455..956edf3bbecb 100644
--- a/include/linux/usb/cdc.h
+++ b/include/linux/usb/cdc.h
@@ -73,6 +73,13 @@ struct usb_cdc_acm_descriptor {
         __u8    bmCapabilities;
 } __attribute__ ((packed));
 
+/* capabilities from 5.2.3.3 */
+
+#define USB_CDC_COMM_FEATURE    0x01
+#define USB_CDC_CAP_LINE        0x02
+#define USB_CDC_CAP_BRK 0x04
+#define USB_CDC_CAP_NOTIFY      0x08
+
 /* "Union Functional Descriptor" from CDC spec 5.2.3.8 */
 struct usb_cdc_union_desc {
         __u8    bLength;