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

[Li Zhang]

On Wed, Aug 15, 2012 at 7:13 PM, David Gibson <address@hidden> wrote:
> On Wed, Aug 15, 2012 at 01:44:28PM +0800, Li Zhang wrote:
>> On Wed, Aug 15, 2012 at 10:57 AM, David Gibson <address@hidden> wrote:
>> > On Wed, Aug 15, 2012 at 10:50:04AM +0800, Li Zhang wrote:
>> >> 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)
>> >> }
>> >
>> > No, this will override the option given on the command line.
>> Oh, I didn't realize that.
>> >
>> >> if (usb_enabled(false)) {  //If vga is enabled and "-machine
>> >> type=pseries" is specified, it will get true.
>> >>     pci_create_simple(ohci)
>> >> }
>> >
>> > It's much easier than this, you just want
>> >         if (usb_enabled(vga_enabled))
>> This is better than mine. :)
>> It seems that this patch needs to work with VGA patch together. :)
>> I need to modify as that. :)
>
> Not necessarily.  In the initial usb pach you can just make the
> default 'false', then just change that one line in the VGA patch.
Got it.
Thanks David. :)

>
> --
> 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