Re: [patch 2.6.19-rc6] fix hotplug for legacy platform drivers

From: Marco d'Itri
Date: Wed Dec 06 2006 - 19:22:33 EST


On Dec 06, David Brownell <david-b@xxxxxxxxxxx> wrote:

> > Please explain in more details how hotplugging would be broken, possibly
> > with examples.
> First, for reference, I refer to hotplugging using the trivial ASH scripts
> from [1], updated by removing no-longer-needed special cases for platform_bus
> (that original logic didn't work sometimes) and pcmcia. See the (short)
I.e. a quick hack which has never been used by any distribution.
And anyway some kernel component is supposed to provide the aliases
pointing from the $MODALIAS values to the drivers, so modprobe $MODALIAS
would still work.

> Those scripts have supported hotplug and coldplug on several embedded boards
> for some time now.
Can you mention some?

> Second, note that you're asking me to construct a straw man for you and
> then break it down, since nobody arguing with the $SUBJECT patch has ever
> provided a complete counter-proposal (much less respond to the points
> I've made about legacy driver bugginess -- which is suggestive).
I am asking what is the point for a module to provide its own name in
$MODALIAS. You say that not doing this would break your custom hotplug
subsystem, but you still have not explained how this would happen since
$MODALIAS is available only *after* the module has been loaded by
something else.

> And "udev" was from day one supposed to solve a different problem
> than "loading modules". There was to be a clear and strong separation
> of roles between hotplug (load modules, don't rely on sysfs, use other
> components for the rest of device setup) and udev (make /dev nodes,
> ok to rely on sysfs). That is, "udev" wouldn't do any loading.
Who cares? It does now, and for many good reasons.

--
ciao,
Marco
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