Re: [RFC PATCH 0/3] introduce: Multistate Switch Class
From: Mark Brown
Date: Mon Dec 05 2011 - 14:45:47 EST
On Tue, Dec 06, 2011 at 06:38:34AM +1100, NeilBrown wrote:
> Ahh..
> So to try to restate the requirements:
> A "cable-port" can detect when a "cable" in inserted (or removed) and can
> determine the "cable-type" which comprises:
> - a "cable-name" which is an arbitrary label interpreted in the context of
> the particular port
> - 1 or more "cable-function" flags which indicate what functions the
> cable support. A given port has a fixed set of "cable-functions" and
> for any given cable it will report true/false (present/absent, on/off)
> for each cable-function.
>
> This full "cable-type" needs to be presented to user-space, and individual
> cable-functions may need to be communicated to specific drivers to trigger a
> 'probe' function.
Yes, that seems broadly sane for me.
> Questions:
> 1/ Do we need to communicate anything to drivers apart from "cable-detect"?
> i.e. are they quite cable of probing and identifying, or do they need to
> be told what to look for?
Perhaps.
> 2/ Does it hurt to simply wake up all drivers that might be listening on
> the cable or do we need individual wake-ups (notifiers) for each
> cable-function?
I suspect not.
> 3/ Does anything in the kernel care about the cable-name, or is that only
> interesting to user-space?
I suspect not.
Other people may have other opinions, though.
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