Re: [Qemu-ppc] [PATCH] spapr/pci: populate PCI DT in reverse order

[Greg Kurz]

On Thu, 3 Dec 2015 15:53:17 +0100
Greg Kurz <address@hidden> wrote:

> On Tue, 1 Dec 2015 22:48:38 +0100
> Thomas Huth <address@hidden> wrote:
> 
> > On 30/11/15 11:45, Greg Kurz wrote:
> > > Since commit 1d2d974244c6 "spapr_pci: enumerate and add PCI device tree", 
> > > QEMU
> > > populates the PCI device tree in the opposite order compared to SLOF.
> > > 
> > > Before 1d2d974244c6:
> > > 
> > > Populating /address@hidden
> > >                      00 0000 (D) : 1af4 1000    virtio [ net ]
> > >                      00 0800 (D) : 1af4 1001    virtio [ block ]
> > >                      00 1000 (D) : 1af4 1009    virtio [ network ]
> > > Populating /address@hidden/address@hidden
> > > 
> > > 
> > > 7e5294b8 :  /address@hidden
> > > 7e52b998 :  |-- address@hidden
> > > 7e52c0c8 :  |-- address@hidden
> > > 7e52c7e8 :  +-- address@hidden ok
> > > 
> > > Since 1d2d974244c6:
> > > 
> > > Populating /address@hidden
> > >                      00 1000 (D) : 1af4 1009    virtio [ network ]
> > > Populating /address@hidden/address@hidden
> > >                      00 0800 (D) : 1af4 1001    virtio [ block ]
> > >                      00 0000 (D) : 1af4 1000    virtio [ net ]
> > > 
> > > 
> > > 7e5e8118 :  /address@hidden
> > > 7e5ea6a0 :  |-- address@hidden
> > > 7e5eadb8 :  |-- address@hidden
> > > 7e5eb4d8 :  +-- address@hidden ok
> > > 
> > > This behaviour change is not actually a bug since no assumptions should be
> > > made on DT ordering. But it has no real justification either, other than
> > > being the consequence of the way fdt_add_subnode() inserts new elements
> > > to the front of the FDT rather than adding them to the tail.
> > > 
> > > This patch reverts to the historical SLOF ordering by walking PCI devices 
> > > in
> > > reverse order.
> > 
> > I've applied your patch here locally, and indeed, the device tree looks
> > nicer to me, too, when the nodes are listed in ascending order.
> > 
> > Tested-by: Thomas Huth <address@hidden>
> > 
> > 
> 

Ping ?

> Thanks for testing !
> 
> Cheers.
> 
> --
> Greg
> 
>