Re: linux-next: manual merge of the xen-two tree with Linus'tree

From: Jan Beulich
Date: Tue Oct 02 2012 - 09:33:58 EST


>>> On 02.10.12 at 14:55, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> wrote:
> On Tue, Oct 02, 2012 at 12:54:20PM +0100, Jan Beulich wrote:
>> >>> On 02.10.12 at 13:45, Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> wrote:
>> >> > Considering that dbgp doesn't seem to be very useful without PCI at the
>> >> > moment, could we just turn it into:
>> >> >
>> >> > dom0-$(CONFIG_PCI) += dbgp.o
>> >> >
>> >> > ?
>> >>
>> >> Better not - the code is specifically not PCI-only. And I can't see
>> >> how it would be harmful to be compiled on e.g. ARM (so the
>> >> merge perhaps really should use XEN_DOM0 alone, without
>> >> X86. If anything (and that may indeed be a minor oversight of
>> >> the original patch) one might want it to depend on USB_SUPPORT,
>> >> as without that no in-tree debug port capable driver would be
>> >> able to load (and hence interfere with Xen's use of the debug
>> >> port). However, as long as it builds fine with USB_SUPPORT
>> >> undefined (which I believe it does), having it in the shape it
>> >> is allows for out-of-tree drivers as well (as long as they make
>> >> use of the designated interface).
>> >
>> > OK for PCI.
>> > Regarding USB_SUPPORT, considering that gbgp.c calls hcd_to_bus, I think
>> > it would make sense to make it depend on it.
>>
>> As said - I'd prefer to do that only if indeed needed to get things
>> to build without that option. Since include/usb/* doesn't reference
>> CONFIG_USB_SUPPORT, I'm in favor of supporting at least those
>> eventual out-of-tree drivers that do use the pre-existing data
>> structures (and others shouldn't be calling pre-existing APIs
>> anyway). But I wouldn't NAK a patch doing what you suggest
>> either.
>
> Could it depend on EARLY_PRINTK_DBGP ?

No, that one would definitely be wrong (because we need the
EHCI driver to propagate reset information no matter whether
the kernel uses an early console).

Jan

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