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Date: Tue, 28 Sep 2010 13:01:32 +0800
Message-ID: <AANLkTimT8WkgiCANL4tXcNgnm63oMnO2d2bKjDD1chJv@mail.gmail.com>
Subject: Re: [PATCH] mfd: speedup twl4030 irq response time and decrease irq
 disable time
From: Ming Lei <tom.leiming@gmail.com>
To: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Samuel Ortiz <sameo@linux.intel.com>, linux-omap@vger.kernel.org,
        Santosh Shilimkar <santosh.shilimkar@ti.com>,
        Balaji T K <balajitk@ti.com>, Rajendra Nayak <rnayak@ti.com>,
        Kevin Hilman <khilman@deeprootsystems.com>,
        linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@elte.hu>, Peter Zijlstra <peterz@infradead.org>,
        linux-arch@vger.kernel.org
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CC genirq guys

2010/9/28 Mark Brown <broonie@opensource.wolfsonmicro.com>:
> On Tue, Sep 28, 2010 at 08:25:24AM +0800, Ming Lei wrote:
>> 2010/9/27 Samuel Ortiz <sameo@linux.intel.com>:
>
>> > Wouldn't converting your twl4030_irq_thread() to the threaded IRQ framework
>> > fix that problem ?
>
>> IRQ_DISABLED flag is set by disable_irq_nosync called from PIH handler,
>> then thread function can't be executed in irq thread function, so we can't
>> convert this to threaded IRQ framework simply.
>
> Have you raised this issue with the genirq guys?  This sounds like
> something that the core infrastructure should be able to cope with.
>

Even genirq guys can help us to convert to irq thread framework, I
don't think there is good way to set priority for one irq thread.

For twl4030, if we can make twl4030_irq_thread to run at higher
priority than that of other irq thread, the PIH irq disable time can be
decreased further since other irq thread waken up by twl4030_irq_thread
can preempt the running of twl4030_irq_thread, and the PIH irq will be
enabled until complete of twl4030_irq_thread.

thanks,
-- 
Lei Ming