Subject: Re: [PATCH] Patch pvr2 driver to allow development of maple bus
	driver
From: Adrian McMenamin <adrian@newgolddream.dyndns.info>
To: Mike Frysinger <vapier@gentoo.org>
Cc: linuxsh-dev@lists.sourceforge.net, Adrian McMenamin <lkmladrian@gmail.com>,
       Paul Mundt <lethal@linux-sh.org>, linux-kernel@vger.kernel.org,
       Mike Frysinger <vapier.adi@gmail.com>
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	 <200708312302.46542.vapier@gentoo.org>
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Date: Sat, 01 Sep 2007 10:35:27 +0100
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On Fri, 2007-08-31 at 23:02 -0400, Mike Frysinger wrote:

> i really dont know how the maple bus works or what piece of hardware is wired 
> up to the same interrupt line.  my point is that if the other device fires an 
> interrupt, the pvr interrupt handler may be executed and attempt to do work 
> when in reality the pvr was not the source of the interrupt.
> -mike

The interrupt is *always* fired by the PVR - it is the VBLANK - ie
essentially screen refresh. It is *never* generated by the maple bus.

However, the maple bus is/can be hardware synced - which means once that
setting is made then the hardware will *always* be polled on the VBLANK.

In other words there is no need to check which device is interrupt is
for, because it is *always* going to be for both of them.
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