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connect low speed host devices to qemu ehci does not work
$ qemu-system-i386 -hda my_x86.img -device ich9-usb-ehci1,id=ehci -device usb-host,vendorid=0x045e,productid=0x071d -serial stdio
qemu-system-i386: Warning: speed mismatch trying to attach usb device "Microsoft? 2.4GHz Transceiver V" ( speed) to bus "ehci.0", port "1" (high speed)
qemu-system-i386: Warning: speed mismatch trying to attach usb device "Microsoft? 2.4GHz Transceiver V" ( speed) to bus "ehci.0", port "1" (high speed)
qemu-system-i386: Warning: speed mismatch trying to attach usb device "Microsoft? 2.4GHz Transceiver V" ( speed) to bus "ehci.0", port "1" (high speed)
Which is obviously wrong. The ehci specification states:
Low-speed device, release ownership of port <= Table 2-16.
Table 2-6:
Number of Companion Controller (N_CC). This field indicates the number of
companion controllers associated with this USB 2.0 host controller.
A zero in this field indicates there are no companion host controllers. Port-ownership
hand-off is not supported. Only high-speed devices are supported on the host controller
root ports.
A value larger than zero in this field indicates there are companion USB 1.1 host
controller(s). Port-ownership hand-offs are supported. High, Full- and Low-speed
devices are supported on the host controller root ports.
Which is not longer true, as for example skylake and baytrail offers a dual usb stack of ehci and xhci. In that case, EHCI handles the low speed device as well.
brgds,
Bert
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