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Date: Wed, 15 Aug 2012 16:05:00 -0500
From: Scott Wood <scottwood@freescale.com>
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To: Kumar Gala <galak@kernel.crashing.org>
Subject: Re: [PATCH V7 2/3] powerpc/ge_imp3a: Add ISA node to PCI primary bus
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Cc: B07421@freescale.com, linuxppc-dev@lists.ozlabs.org,
 Jia Hongtao <B38951@freescale.com>
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On 08/15/2012 04:01 PM, Kumar Gala wrote:
> 
> On Aug 15, 2012, at 12:31 PM, Scott Wood wrote:
> 
>> On 08/15/2012 03:57 AM, Jia Hongtao wrote:
>>> PCI primary bus will be determined by looking for ISA node in device tree.
>>> Also for board ge_imp3a primary bus is the second PCI controller detected.
>>> So we add ISA node to ge_imp3a's device tree to fit the new determination.
>>>
>>> Adding ISA node to other boards' device tree is not necessary. The situation
>>> that the first bus is primary have already been handled. Please refer to the
>>> following patch:
>>> powerpc/pci: Make sure ISA IO base is not zero
>>>
>>> Signed-off-by: Jia Hongtao <B38951@freescale.com>
>>> Signed-off-by: Li Yang <leoli@freescale.com>
>>> ---
>>> arch/powerpc/boot/dts/ge_imp3a.dts |    4 ++++
>>> 1 files changed, 4 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/arch/powerpc/boot/dts/ge_imp3a.dts b/arch/powerpc/boot/dts/ge_imp3a.dts
>>> index fefae41..aa2c4b5 100644
>>> --- a/arch/powerpc/boot/dts/ge_imp3a.dts
>>> +++ b/arch/powerpc/boot/dts/ge_imp3a.dts
>>> @@ -248,6 +248,10 @@
>>> 				  0x1000000 0x0 0x0
>>> 				  0x1000000 0x0 0x0
>>> 				  0x0 0x10000>;
>>> +
>>> +			isa@1e {
>>> +				device_type = "isa";
>>> +			};
>>> 		};
>>> 	};
>>> };
>>
>> I believe I already said it's not acceptable to break old device trees.
>>
>> -Scott
>>
> 
> I agree w/Scott this is NOT an acceptable solution, both because of
> old device tree and its just wrong to list ISA if it doesn't exist in
> the device.

If there isn't actually ISA here, why do we care which bus is primary?
Other than the lack of hardware to sanity test the change on...

-Scott