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Diffstat (limited to 'docs/usb2.txt')
| -rw-r--r-- | docs/usb2.txt | 33 |
1 files changed, 28 insertions, 5 deletions
diff --git a/docs/usb2.txt b/docs/usb2.txt index 5950c713e9..228aa33ceb 100644 --- a/docs/usb2.txt +++ b/docs/usb2.txt @@ -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 ====================== |