Message-ID: <4562B35C.7090807@s5r6.in-berlin.de>
Date: Tue, 21 Nov 2006 09:05:48 +0100
From: Stefan Richter <stefanr@s5r6.in-berlin.de>
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To: Alan Stern <stern@rowland.harvard.edu>
CC: linux1394-devel@lists.sourceforge.net, Greg Kroah-Hartman <gregkh@suse.de>,
       linux-kernel@vger.kernel.org, Dmitry Torokhov <dtor@insightbb.com>
Subject: Re: deadlock in "modprobe -r ohci1394" shortly after "modprobe ohci1394"
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Alan Stern wrote:
> The real issue here is the way ieee1394 sets up children of devices with
> no driver.  On the face of it that is quite illogical: If a device has no
> driver, then who can interrogate it to find out about its children?

Perhaps I should turn this dummy driver into an actual representation of
ieee1394 or ieee1394's nodemgr.

> USB faces a similar situation.  In a USB device, all the real work is 
> actually done by "interfaces".  So we set up a device structure for the 
> USB device itself, plus device structures for each of its interfaces.  The 
> parent structure is bound to a (more or less) dummy driver, which insures 
> that the child structures are deleted whenever it gets unbound.

I will eventually more thoroughly look at how USB and other subsystems
with device hierarchies do it.

> Still, maybe some compromise can be reached.  Perhaps Dmitry's idea, or 
> something like it, can be adopted.

Thanks for the input of both of you.
-- 
Stefan Richter
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http://arcgraph.de/sr/
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