[Qemu-devel] [Bug 1550743] [NEW] connect low speed host devices to qemu ehci does not work

[Bert Brecht]

Public bug reported:

$ 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

** Affects: qemu
     Importance: Undecided
         Status: New


** Tags: ehci usb

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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:
  New

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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