Re: [RFC] driver-core: Remove dummy 'platform_bus'

[Grant Likely]

On Thu, Nov 22, 2012 at 7:17 PM, Kay Sievers <kay@xxxxxxxx> wrote:
> On Wed, Nov 21, 2012 at 3:52 PM, Greg Kroah-Hartman
> <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>> On Wed, Nov 21, 2012 at 02:44:31PM +0000, Grant Likely wrote:
>>> The "platform_bus" (note: not platform_bus_type) only exists as an empty
>>> directory to put platform devices into. However, it really doesn't make
>>> sense to segregate all the platform devices into a sub directory when
>>> typically they are memory mapped devices that doen't go through any
>>> particular bus. Particularly on embedded type platforms the platform_bus
>>> directory doesn't add anything.
>>>
>>> However, this will probably just end up breaking some userspace that
>>> depends on the /sys/devices/platform/ path to be present (no matter how
>>> much we protest that userspace must not depend on paths in sysfs). So
>>> while I'm seriously proposing this change, it may just be unacceptable
>>> ABI breakage
>>
>> If the devices don't show up under platform/ where are they going to be
>> at now, virtual/ ?  That doesn't sound like a good plan, they should be
>> somewhere "useful".
>
> Just a note to keep in mind: We usually need and want devices to have
> a bus or class. Devices without a "subsystem" are invisible to udev,
> and do not get proper coldplug support at bootup.

Note: this patch is only about the "platform_bus" dummy device. It has
nothing to do with platform_bus_type.

g.
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