Are you sure that EHCI handles low-speed devices in that case? I thought that
XHCI is capable of handling low-speed devices instead...
Anyway, QEMU certainly only emulates the EHCI in a traditional way, so if you
want to use low-speed devices here, you also have to specify an UHCI controller
for them. I.e. as far as I can see, this is not a bug in QEMU, but just a
configuration issue.
** Changed in: qemu
Status: New => Invalid
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https://bugs.launchpad.net/bugs/1550743
Title:
connect low speed host devices to qemu ehci does not work
Status in QEMU:
Invalid
Bug description:
$ 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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