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From: "Dmitry Torokhov" <dmitry.torokhov@gmail.com>
To: "Ahmed S. Darwish" <darwish.07@gmail.com>
Cc: "Bryan Wu" <bryan.wu@analog.com>,
	linux-input@atrey.karlin.mff.cuni.cz,
	linux-joystick@atrey.karlin.mff.cuni.cz,
	linux-kernel@vger.kernel.org, akpm@linux-foundation.org
Subject: Re: [PATCH try #2] Input/Joystick Driver: add support AD7142 joystick driver
Date: Fri, 12 Oct 2007 16:23:15 -0400	[thread overview]
Message-ID: <d120d5000710121323w563cf328s315f95eb6a857b75@mail.gmail.com> (raw)
In-Reply-To: <20071012192111.GB12559@Ahmed>

On 10/12/07, Ahmed S. Darwish <darwish.07@gmail.com> wrote:
> On Fri, Oct 12, 2007 at 01:29:31PM -0400, Dmitry Torokhov wrote:
> >
> > > Isn't disabling device interrupts from the begining of the ISR "ad7142_interrupt"
> > > till the kthread "ad7142_thread" got waked-up and scheduled a long time,
> > > espicially if there's a high load on the userspace side ?
> > >
> >
> > It is OK - you disable a specific interrupt line preventing it from
> > raising any more IRQs until current one is serviced.
>
> Won't this affect system responsiveness if the IRQ line was shared ?

You are right, this would not work in case of shared IRQs. Hovewer
this driver is for an embedded arch and the line is not shared.

>
> >
> > This is different from disabling interrupts on CPU.
> >
>
> mm, Why disabling interrupts in general. Doesn't IRQ hanlers of the same kind got
> executed in a serialized fashion even on SMPs ?. If so, why not just wakeup our
> custom-thread or use workqueues and let them do their business ?

Because you don't want CPU to be continually interrupted while untill
right thread gets scheduled. I think using work[queue] is the best
solution for this driver, but you still want to mask that particular
IRQ off until you do the read.

-- 
Dmitry

      reply	other threads:[~2007-10-12 20:23 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-10-12  7:38 Bryan Wu
2007-10-12  7:51 ` Andrey Panin
2007-10-12  9:14 ` Roel Kluin
2007-10-12 14:49 ` Dmitry Torokhov
2007-10-12 15:39   ` Bryan Wu
2007-10-12 15:50     ` Dmitry Torokhov
2007-10-12 15:59       ` Bryan Wu
2007-10-12 16:14         ` Dmitry Torokhov
2007-10-12 16:41 ` Ahmed S. Darwish
2007-10-12 17:29   ` Dmitry Torokhov
2007-10-12 19:21     ` Ahmed S. Darwish
2007-10-12 20:23       ` Dmitry Torokhov [this message]

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