usb: update documentation

Add a paragraph on companion controller mode and a
configuration file which sets it all up for you.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This commit is contained in:
Gerd Hoffmann 2011-07-05 16:58:41 +02:00
parent 3028376ea0
commit 76f30473da
2 changed files with 65 additions and 5 deletions

37
docs/ich9-ehci-uhci.cfg Normal file
View file

@ -0,0 +1,37 @@
###########################################################################
#
# You can pass this file directly to qemu using the -readconfig
# command line switch.
#
# This config file creates a EHCI adapter with companion UHCI
# controllers as multifunction device in PCI slot "1d".
#
# Specify "bus=ehci.0" when creating usb devices to hook them up
# there.
#
[device "ehci"]
driver = "ich9-usb-ehci1"
addr = "1d.7"
multifunction = "on"
[device "uhci-1"]
driver = "ich9-usb-uhci1"
addr = "1d.0"
multifunction = "on"
masterbus = "ehci.0"
firstport = "0"
[device "uhci-2"]
driver = "ich9-usb-uhci2"
addr = "1d.1"
multifunction = "on"
masterbus = "ehci.0"
firstport = "2"
[device "uhci-3"]
driver = "ich9-usb-uhci3"
addr = "1d.2"
multifunction = "on"
masterbus = "ehci.0"
firstport = "4"

View file

@ -2,11 +2,13 @@
USB 2.0 Quick Start
===================
The QEMU EHCI Adapter does *not* support companion controllers. That
implies there are two completely separate USB busses: One USB 1.1 bus
driven by the UHCI controller and one USB 2.0 bus driven by the EHCI
controller. Devices must be attached to the correct controller
manually.
The QEMU EHCI Adapter can be used with and without companion
controllers. See below for the companion controller mode.
When not running in companion controller mode there are two completely
separate USB busses: One USB 1.1 bus driven by the UHCI controller and
one USB 2.0 bus driven by the EHCI controller. Devices must be
attached to the correct controller manually.
The '-usb' switch will make qemu create the UHCI controller as part of
the PIIX3 chipset. The USB 1.1 bus will carry the name "usb.0".
@ -32,6 +34,27 @@ This attaches a usb tablet to the UHCI adapter and a usb mass storage
device to the EHCI adapter.
Companion controller support
----------------------------
Companion controller support has been added recently. The operational
model described above with two completely separate busses still works
fine. Additionally the UHCI and OHCI controllers got the ability to
attach to a usb bus created by EHCI as companion controllers. This is
done by specifying the masterbus and firstport properties. masterbus
specifies the bus name the controller should attach to. firstport
specifies the first port the controller should attach to, which is
needed as usually one ehci controller with six ports has three uhci
companion controllers with two ports each.
There is a config file in docs which will do all this for you, just
try ...
qemu -readconfig docs/ich9-ehci-uhci.cfg
... then use "bus=ehci.0" to assign your usb devices to that bus.
More USB tips & tricks
======================