linux-kernel - Re: [PATCH v2] [ARM] gic: Unmask private interrupts on all cores during IRQ enable

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Date:	Wed, 01 Dec 2010 11:36:10 -0500
From:	Stephen Caudle <scaudle@...eaurora.org>
To:	Russell King - ARM Linux <linux@....linux.org.uk>
CC:	dwalker@...eaurora.org, linux-arm-msm@...r.kernel.org,
	adharmap@...eaurora.org, linux-kernel@...r.kernel.org,
	miltonm@....com, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2] [ARM] gic: Unmask private interrupts on all cores
 during IRQ enable

On 11/30/2010 01:07 PM, Russell King - ARM Linux wrote:
> Sorry, missed this.
>
> If it's a private peripheral, it can only be accessed from its associated
> CPU.  What that means is you don't want to enable the interrupt on other
> CPUs as the peripheral may not be present or initialized on that CPU.

Understood.  But the alternative is to require all code that requests a 
PPI to have to enable the IRQ on the other cores.  This seems 
unreasonable to me.

> So I'm nervous about this change - architecturally it feels like the
> wrong thing to do to take the PPI interrupts through the generic IRQ
> infrastructure.

What do suggest as an alternative to this solution?  Creating separate 
IRQ numbers for each core (per PPI) doesn't seem to scale well as the 
number of cores increase.

~Stephen

-- 
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
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