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Re: [Qemu-devel] [Qemu-ppc] [PATCH] spapr/pci: populate PCI DT in revers
From: |
Greg Kurz |
Subject: |
Re: [Qemu-devel] [Qemu-ppc] [PATCH] spapr/pci: populate PCI DT in reverse order |
Date: |
Thu, 3 Dec 2015 15:53:17 +0100 |
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>
>
>
Thanks for testing !
Cheers.
--
Greg