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Subject: Re: [RFC 1/3] hvc_console: rework setup to replace irq functions
	with callbacks (not word wrapped)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reply-To: benh@kernel.crashing.org
To: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Linux PPC devel <linuxppc-dev@ozlabs.org>,
       Virtualization Mailing List <virtualization@lists.osdl.org>,
       Jeremy Fitzhardinge <jeremy@goop.org>,
       Rusty Russell <rusty@rustcorp.com.au>,
       LKML <linux-kernel@vger.kernel.org>
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	 <200806031449.14385.borntraeger@de.ibm.com>
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Date: Wed, 04 Jun 2008 19:06:42 +1000
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On Tue, 2008-06-03 at 14:49 +0200, Christian Borntraeger wrote:
> This patch tries to change hvc_console to not use request_irq/free_irq if
> the backend does not use irqs. This allows virtio_console to use hvc_console
> without having a linker reference to request_irq/free_irq.
> 
> The irq specific code is moved to hvc_irq.c and selected by the drivers that
> use irqs (System p, System i, XEN).
> 
> I replaced "irq" with the opaque name "data". The request_irq and free_irq
> calls are replaced with notifier_add and notifier_del. I have also changed
> the code a bit to call the notifier_add and notifier_del inside the spinlock
> area as the callbacks are found via hp->ops.
> 
> Feedback is appreciated.

I haven't looked at the patch proper but I agree with the basic
premises. We routinely use hvc_console for things that don't have an
irq. In fact, David even did a backend hooking up to udbg which is
useful when bringing up weird stuffs :-)

Cheers,
Ben.