Message-ID: <50703B1B.2040705@linux.intel.com>
Date: Sat, 06 Oct 2012 22:07:23 +0800
From: Haicheng Li <haicheng.li@linux.intel.com>
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To: David Miller <davem@davemloft.net>
CC: fengguang.wu@intel.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [net:master 1/9] pch_gbe_main.c:(.text+0x510370): undefined reference
 to `pch_ch_control_write'
References: <20121006075954.GA29618@localhost>	<50701EEC.7080805@linux.intel.com> <20121006.092207.1280541690613202532.davem@davemloft.net>
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On 10/06/2012 09:22 PM, David Miller wrote:
> From: Haicheng Li<haicheng.li@linux.intel.com>
> Date: Sat, 06 Oct 2012 20:07:08 +0800
>
>> The failure is due to the CONFIG_PPS is not set there, consequently
>> CONFIG_PTP_1588_CLOCK can not be set as =y anyway.
>>
>> So David's patch of "da1586461e53a4dd045738cce309ab488970f0ef [1/9]
>> pch_gbe: Fix PTP dependencies" is buggy. Furthermore, I think using
>> "selects" to resolve such dependency issue is not good idea as it
>> won't visit the dependencies.
>>
>> David, I would still suggest to take my original patch:
>> https://lkml.org/lkml/2012/9/28/70
>>
>> + depends on PTP_1588_CLOCK_PCH&&  (PCH_GBE=m || PTP_1588_CLOCK_PCH=y)
>>
>> or simply like:
>
> This is all very rediculous if you ask me.
>
> Why should the user have to know a detail like the underlying
> PTP chip type just to enable PTP on his networking card?
>
> Because that is what you are making him do with your change.
>
> Select removed the necessity of the user having to know these
> things.
However it possibly breaks the build...

IMHO, the reason why the dependency of PCH_PTP becomes so tricky is that the 
code of these two modules call the functions of each other (bad code 
structure?). To fix it neatly, either we restructure the code or just simply 
make it:
+ depends on PTP_1588_CLOCK_PCH=y

For PCH_GBE=m case, it does be able to pass the build test, but I'm afraid it 
won't be smoothly workable via "insmod" due to the codependency of these two 
when PCH_PTP is enabled.

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