Subject: Re: OHCI root_port_reset() deadly loop...
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reply-To: benh@kernel.crashing.org
To: David Miller <davem@davemloft.net>
Cc: greg@kroah.com, david-b@pacbell.net, linux-usb-users@lists.sourceforge.net,
       linux-kernel@vger.kernel.org
In-Reply-To: <20071008.214727.48799757.davem@davemloft.net>
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	 <20071009043909.GA4940@kroah.com>
	 <20071008.214727.48799757.davem@davemloft.net>
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Date: Tue, 09 Oct 2007 15:11:41 +1000
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On Mon, 2007-10-08 at 21:47 -0700, David Miller wrote:
> From: Greg KH <greg@kroah.com>
> Date: Mon, 8 Oct 2007 21:39:09 -0700
> 
> > No, nothing cute in udev itself, but it seems that all distros that I
> > know of have a "load these modules now" type setting in their init
> > scripts that can be used here.
> > 
> > I can't think of a way to enforce this load order on the modules
> > themselves due to the fact that OHCI might not even be needed for EHCI
> > devices on UHCI (Intel) based chipsets :(
> > 
> > Can anyone else?
> 
> The three modules perhaps should be a bundle of whatever ones you have
> enabled, and internally we can dispatch the initialization to occur in
> the correct order from a top-level module_init().
> 
> If the devices need to be initialized in a certain order in a
> situation like this, it really seems like it is the kernel's job to
> enforce it.

Is the problem strictly an ordering problem or just a race ? In the
later case, maybe some better arbitration by the USB core to make
sure things are quiescent or in a known state when letting a new HCD
register might help ?

Ben.


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