Re: [Qemu-ppc] commit 094b287 "Add USB option in machine options" broke i386 -usb

[Peter Maydell]

On 22 November 2012 16:34, Li Zhang <address@hidden> wrote:
> On 2012年11月23日 00:18, Peter Maydell wrote:
>>
>> On 29 October 2012 10:25, Alexander Graf <address@hidden> wrote:
>>>
>>> From: address@hidden <address@hidden>
>>>
>>> When -usb option is used, global varible usb_enabled is set.
>>> And all the plaform will create one USB controller according
>>> to this variable. In fact, global varibles make code hard
>>> to read.
>>>
>>> So this patch is to remove global variable usb_enabled and
>>> add USB option in machine options. All the plaforms will get
>>> USB option value from machine options.
>>>
>>> USB option of machine options will be set either by:
>>>    * -usb
>>>    * -machine type=pseries,usb=on
>>>
>>> Both these ways can work now. They both set USB option in
>>> machine options. In the future, the first way will be removed.
>>
>> This commit breaks "qemu-system-i386 -usb", which used to
>> create a USB bus and now does not. Example to reproduce:
>>
>> $ dd if=/dev/zero bs=4096 count=1024 of=usb.img
>> $ ./i386-softmmu/qemu-system-i386 -clock unix -monitor stdio -usb
>> -drive if=none,file=usb.img,id=myusb  -device
>> usb-storage,id=myusb,drive=myusb,removable=on
>
> Hi Peter,
>
> I am sorry to cause this problem.
>
> I couldn't see  the machine's option in your command line.
> such as, -machine type=pc
>
> As it describes, you need to pass this option to enable USB.
> Because USB option is set by machine's option.

We use "-usb" to enable USB in this command line. That has
to continue to work, for back compatibility. I think your
code to try to support -usb is broken:
  case QEMU_OPTION_usb:
    machine_opts = qemu_opts_find(qemu_find_opts("machine"), 0);

will return NULL if there are no user-set machine opts
at this point, so we never go on to try to set the usb
machine opt to true.

-- PMM