Re: [net:master 1/9] pch_gbe_main.c:(.text+0x510370): undefined referenceto `pch_ch_control_write'

[Haicheng Li]

On 10/06/2012 10:21 PM, David Miller wrote:
> From: Haicheng Li<haicheng.li@xxxxxxxxxxxxxxx>
> Date: Sat, 06 Oct 2012 22:07:23 +0800
>
> > On 10/06/2012 09:22 PM, David Miller wrote:
> > > From: Haicheng Li<haicheng.li@xxxxxxxxxxxxxxx>
> > > 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.
>
> Then why does it work for IXGBE and others who use select?

They explicitly select all the possible dependencies if they are bug-free (I 
didn't strictly check them).

Take IXGBE_PTP as example, it explicitly selects PPS, and also depends on 
EXPERIMENTAL:
config IXGBE_PTP
        bool "PTP Clock Support"
        default n
        depends on IXGBE && EXPERIMENTAL
        select PPS
        select PTP_1588_CLOCK

So if you stick to use "select" as the convention of such build issue fixing, 
fengguang's build failure would be fixed by:
	+ depends on EXPERIMENTAL
	+ select PPS
	+ select PTP_1588_CLOCK

would you prefer this way?

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