[SLOF] Keyboard not working when using XHCI as a USB host controller?

[Nikunj A Dadhania]

Nikunj A Dadhania <nikunj at linux.vnet.ibm.com> writes:

> Thomas Huth <thuth at redhat.com> writes:
>
>>  Hi!
>>
>> When I use the following command line to start a guest:
>>
>>  qemu-system-ppc64 -machine pseries,accel=kvm,usb=off \
>> 	-device pci-ohci,id=usb,bus=pci.0,addr=0x2 \
>> 	-device usb-kbd,id=input0 -nographic -vga none
>>
>> ... SLOF correctly discoveres a keyboard during USB scan:
>>
>>  Scanning USB 
>>    OHCI: initializing
>>      USB Keyboard 
>>  ...
>>  0 > devalias  
>>  keyboard : /pci at 800000020000000/usb at 2/usb-keyboard at 1
>>  usb0 : /pci at 800000020000000/usb at 2
>>  ...
>>
>> However, when I start with an XHCI (or EHCI) controller
>> instead:
>>
>>  qemu-system-ppc64 -machine pseries,accel=kvm,usb=off \
>> 	-device nec-usb-xhci,id=usb,bus=pci.0,addr=0x2 \
>> 	-device usb-kbd,id=input0 -nographic -vga none
>>
>> ... SLOF does not discover any keyboard:
>>
>>  Scanning USB 
>>    XHCI: Initializing
>>   ...
>>  0 > devalias  
>>  usb0 : /pci at 800000020000000/usb at 2
>>  ...
>>
>> Is this supposed to work? Am I doing something wrong?
>
> No, I have never tested this configuration.
>
> I tried enabling debugs in lib/libusb/usb-xhci.c, I dont see the port
> reporting on this device.
>
> info qtree gives this:
>
>     bus: pci.0
>       type PCI
>       dev: nec-usb-xhci, id "usb"
>         msi = true
>         msix = true
>         superspeed-ports-first = true
>         force-pcie-endcap = false
>         streams = true
>         intrs = 16 (0x10)
>         slots = 64 (0x40)
>         p2 = 4 (0x4)
>         p3 = 4 (0x4)
>         addr = 02.0
>         romfile = ""
>         rombar = 1 (0x1)
>         multifunction = false
>         command_serr_enable = true
>         class USB controller, addr 00:02.0, pci id 1033:0194 (sub 1af4:1100)
>         bar 0: mem at 0x100000000 [0x100003fff]
>         bus: usb.0
>           type usb-bus
>           dev: usb-kbd, id "input0"
>             usb_version = 2 (0x2)
>             display = ""
>             port = ""
>             serial = ""
>             full-path = true
>             msos-desc = true
>             addr 0.0, port 1, speed 480, name QEMU USB Keyboard, attached
>
>
> I suspect that usb-version = 2 would be the reason, the code does not
> see this port.


Here you go:
Section 7.0 and 7.2 of xHCI specs

		if (XHCI_XECP_CAP_ID(read_reg32(xecp_addr)) == XHCI_XECP_CAP_SP &&
		    XHCI_XECP_CAP_SP_MJ(read_reg32(xecp_addr)) == 3 &&
		    XHCI_XECP_CAP_SP_MN(read_reg32(xecp_addr)) == 0) {
			port_cnt = XHCI_XECP_CAP_SP_PC(read_reg32(xecp_addr + 2));
			port_off = XHCI_XECP_CAP_SP_PO(read_reg32(xecp_addr + 2));

So we scan 3.0 ports, and as its reported as 2.0, it would not appear
in the port list.

Regards
Nikunj