From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Dmitry Torokhov" Subject: Re: [PATCH try #2] Input/Joystick Driver: add support AD7142 joystick driver Date: Fri, 12 Oct 2007 16:23:15 -0400 Message-ID: References: <1192174727.6247.20.camel@roc-laptop> <20071012164131.GA12559@Ahmed> <20071012192111.GB12559@Ahmed> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20071012192111.GB12559@Ahmed> Content-Disposition: inline Sender: owner-linux-input@atrey.karlin.mff.cuni.cz List-Help: List-Owner: List-Post: List-Unsubscribe: To: "Ahmed S. Darwish" Cc: Bryan Wu , linux-input@atrey.karlin.mff.cuni.cz, linux-joystick@atrey.karlin.mff.cuni.cz, linux-kernel@vger.kernel.org, akpm@linux-foundation.org List-Id: linux-input@vger.kernel.org On 10/12/07, Ahmed S. Darwish 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