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Date: Fri, 26 Mar 2010 10:20:23 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Thomas Gleixner <tglx@linutronix.de>, Nicolas Pitre <nico@fluxnic.net>,
       Linus Torvalds <torvalds@osdl.org>, LKML <linux-kernel@vger.kernel.org>,
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       David Miller <davem@davemloft.net>, Greg Kroah-Hartman <gregkh@suse.de>,
       Arnaldo Carvalho de Melo <acme@redhat.com>,
       Russell King <rmk@arm.linux.org.uk>
Subject: Re: [patch 0/2] Run interrupt handlers always with interrupts
 disabled
Message-ID: <20100326092023.GH27394@elte.hu>
References: <20100326000325.917127328@linutronix.de>
 <20100326081457.GA23570@flint.arm.linux.org.uk>
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* Russell King <rmk@arm.linux.org.uk> wrote:

> On Fri, Mar 26, 2010 at 12:06:44AM -0000, Thomas Gleixner wrote:
> > The following patch series removes the IRQF_DISABLED functionality
> > from the core interrupt code and runs all interrupt handlers with
> > interrupts disabled.
> 
> As was covered in previous discussions, what about drivers such as SMC91x 
> which take a long time to retrieve packets from the hardware? Always running 
> handlers with IRQs disabled will kill things such as serial on these 
> platforms.

As long as it's rare (which it is) i dont see a problem: you can enable 
interrupts in the handler by using local_irq_enable(), like the IDE PIO 
drivers do. That way it's documented a bit better as well, because it shows 
the precise source of the latency, with a big comment explaining it, etc.

Thanks,

	Ingo