[OE-core] in meta-yocto-bsp kernel recipes, why individual settings for COMPATIBLE_MACHINE?

[Robert P. J. Day]

On Mon, 27 Feb 2017, Robert P. J. Day wrote:

>
>   more nitpicky pedantry ... under
> meta-yocto-bsp/recipes-kernel/linux, i see a number of
> COMPATIBLE_MACHINE settings:
>
>   COMPATIBLE_MACHINE_genericx86 = "genericx86"
>   COMPATIBLE_MACHINE_genericx86-64 = "genericx86-64"
>   COMPATIBLE_MACHINE_edgerouter = "edgerouter"
>   COMPATIBLE_MACHINE_beaglebone = "beaglebone"
>   COMPATIBLE_MACHINE_mpc8315e-rdb = "mpc8315e-rdb"
>
> given that every one of those conditional assignments match *exactly*
> the respective target system, how does that effectively differ from
> just writing (issues with RE matching aside):
>
>   COMPATIBLE_MACHINE = "(genericx86|genericx86-64|edgerouter|beaglebone|mpc8315e-rdb)"
>
> i can certainly see how one might need to use conditional assignments
> for COMPATIBLE_MACHINE if one has, say, extended the definition of
> MACHINEOVERRIDES to classify target systems into compatible subgroups,
> but that's not what's happening above. is there something more subtle
> going on there that i'm missing?

  never mind, it just dawned on me that those override-based
assignments will leave any earlier assignments in place, rather than
wiping them out. but in the cases where you really just want to
hardcode a set of compatible machines, using that single like still
looks perfectly acceptable.

rday

-- 

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Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

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