Re: arm qemu test failures due to 'driver-core: platform: probe of-devices only using list of compatibles'

From: Russell King - ARM Linux
Date: Mon Feb 15 2016 - 05:04:29 EST


On Mon, Feb 15, 2016 at 10:14:06AM +0100, Uwe Kleine-König wrote:
> Hello Russell,
>
> On Mon, Feb 15, 2016 at 08:58:18AM +0000, Russell King - ARM Linux wrote:
> > On Mon, Feb 15, 2016 at 09:17:50AM +0100, Uwe Kleine-König wrote:
> > > On Sun, Feb 14, 2016 at 08:07:55PM +0000, Russell King - ARM Linux wrote:
> > > > On Sun, Feb 14, 2016 at 08:55:01PM +0100, Uwe Kleine-König wrote:
> > > > > So the unexpected abnormality here is that even though this device is
> > > > > instantiated by dt, the driver doesn't provide any compatibles.
> > > > > Either my expectation is wrong, then 67d02a1bbb33455 should be reverted
> > > >
> > > > Your expectation is wrong. AMBA primecell devices have hardware IDs
> > > > and are matched to their drivers by those IDs. Just like PCI.
> > >
> > > pci devices don't appear in dt, do they? I don't see the connection
> > > between amba devices and platform devices, see my other mail in this
> > > thread for some more details.
> >
> > They both have hardware IDs, and they are both matched via those hardware
> > IDs.
>
> I changed platform_match which is about matching by dt compatible, acpi
> and/or device name. I don't see how this can affect an amba device given
> they match to a driver by a hardware id.
>
> > Your change has introduced a regression and is therefore wrong.
>
> I'd like to understand though why and how my commit is wrong to be able
> to fix it instead of getting it reverted.

I don't have the commit, and I haven't seen the patch so I can't
comment further, sorry.

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