Re: [Xen-devel] [PATCH V1 17/29] xen/arm: Mark each device used by Xen as disabled in DOM0 FDT

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2013-09-09 at 22:53 +0100, Julien Grall wrote:
> On 09/09/2013 12:37 PM, Ian Campbell wrote:
> > On Wed, 2013-08-28 at 15:47 +0100, Julien Grall wrote:
> >> When a device has a property status with disabled inside, Linux will not 
> >> use
> >> the device.
> >
> > Do we not filter such devices out already?
> 
> We only filter gic/timer node. All the others nodes used by Xen, for 
> instance the serial device, will be marked by status = "disabled".

Ah, the current code omits devices from the mapping but not the fdt, I
was confusing the two. In the current way of doing things
fdt_next_dom0_node would need a check for the owner, but that's not
relevant with this series.

> > Or did the previous patch remove that functionality? In which case is
> > there a bisection hazard here?
> 
> AFAIK, there is no bisection hazard with the current order of this patch 
> series.

Ack, thanks.

> 
> >
> > Why is it preferred to leave the device with disabled in it instead of
> > removing it? (Can this go in the changelog please)
> > I think I've asked before, but is the handling of status = disabled
> > generic and therefore reliable?
> 
> I let this patch because I didn't implement all the fake nodes in the 
> previous patch series. In another hand, I'm not sure how Linux will 
> react if there is a missing node and it should cope with status = 
> "disabled" with most of nodes.
> 
> I will give a try and see if I can remove completely nodes used by Xen. 
> Except, of course, gic and timer nodes which are recreated later.

If you want you can add that to the end of the series/future work rather
than reworking this patch in the middle of a large series.



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