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

[Li Zhang <zhlcindy@linux.vnet.ibm.com>]

On 2012年11月23日 00:44, Alexander Graf wrote:
> On 22.11.2012, at 17:39, Peter Maydell wrote:
>
>> On 22 November 2012 16:34, Li Zhang <zhlcindy@linux.vnet.ibm.com> wrote:
>>> On 2012年11月23日 00:18, Peter Maydell wrote:
>>>> On 29 October 2012 10:25, Alexander Graf <agraf@suse.de> wrote:
>>>>> From: zhlcindy@gmail.com <zhlcindy@gmail.com>
>>>>>
>>>>> 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.
> That logic should probably be changed. All the checks whether machine_opts exist are really quite annoying.
OK. I will remove all the checks.
Sorry about that.
>
> Alex
>


-- 

Li Zhang
IBM China Linux Technology Centre