[Qemu-devel] [PATCH v2 0/4]usb: implement Interface Association Descriptor support

[Brad Hards]

These descriptors are covered in Section 9.6.4 of the USB 3.0 spec, 
but there is a better description in the Intel IAD whitepaper 
(www.usb.org/developers/whitepapers/iadclasscode_r10.pdf).

The short version is that IAD is an extra descriptor type that appears before 
a group (two or more) interface descriptors, that explains which interface 
descriptors make up a virtual device.  So it could look like:
Config Desc
IAD#0
Iface#0
Iface#1
Iface#2
IAD#1
Iface#3
Iface#4

[Check the diagram in the Intel IAD whitepaper if that makes no sense]

The implementation basically introduces the concept of a grouped of
interfaces (with an IAD header), and support for sending it to the
device.

The intended use for this is USB Video class devices, which have a
Control interface and Streaming interface that are a single logical
device.

Changes v2 (from v1):
 - Added Signed-off-by, per CODING_STYLE
 - Fixed bug in altsetting handling (.nif needed instead of .bNumInterfaces)
 - Fixed some whitespace and line-length problems indicated by checkstyle.pl

Diffstat:
 usb-desc.c   |   52 +++++++++++++++++++++++++++++++++++++++++++++++++---
 usb-desc.h   |   20 ++++++++++++++++++++
 usb-hid.c    |    3 +++
 usb-hub.c    |    1 +
 usb-msd.c    |    2 ++
 usb-serial.c |    1 +
 usb-wacom.c  |    1 +
 usb.h        |    2 ++
 8 files changed, 79 insertions(+), 3 deletions(-)