Re: [Qemu-devel] [Qemu-ppc] [PATCH v7 1/3] Add USB option in machine options

[Li Zhang]

On Wed, Aug 15, 2012 at 9:47 AM, David Gibson <address@hidden> wrote:
> On Wed, Aug 15, 2012 at 09:24:34AM +0800, Li Zhang wrote:
>> On Wed, Aug 15, 2012 at 8:09 AM, Benjamin Herrenschmidt
>> <address@hidden> wrote:
>> > On Wed, 2012-08-15 at 09:10 +1000, David Gibson wrote:
>> >> > I see. I will redo this patch. Send out it later. :)
>> >> > Thanks for your comments.
>> >>
>> >> When you do that, please also change the default to make spapr _not_
>> >> have usb.
>> >
>> > FYI, I originally asked for USB as default ... however it looks like at
>> > this stage the price (performance) is too high so either make it default
>> > to OFF, or make it default to ON if and only if VGA is also enabled.
>> >
>> Got it, I change the default as false, and when VGA is enabled, set
>> USB option as true.
>
> Not quite, actually.  The default should depend on VGA, but the
> explicit usb= option should always override that.  Having VGA without
> USB would be unusual, but it should be possible if you specify it
> explicitly.
>
Right, explicit usb= option will override the value.
I think we can set the usb option value when no usb option is specified.
For example, we use -machine type=pseries  without usb= option.

I am considering as the following:

if (vga_enabled) {
    set_usb_option(true)
}
if (usb_enabled(false)) {  //If vga is enabled and "-machine
type=pseries" is specified, it will get true.
    pci_create_simple(ohci)
}

> --
> David Gibson                    | I'll have my music baroque, and my code
> david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
>                                 | _way_ _around_!
> http://www.ozlabs.org/~dgibson
>



-- 

Best Regards
-Li