From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753265Ab2LQQGv (ORCPT ); Mon, 17 Dec 2012 11:06:51 -0500 Received: from mail-lb0-f174.google.com ([209.85.217.174]:55979 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752678Ab2LQQGs (ORCPT ); Mon, 17 Dec 2012 11:06:48 -0500 Message-ID: <50CF4313.1010706@gmail.com> Date: Mon, 17 Dec 2012 17:06:43 +0100 From: =?UTF-8?B?TWFyY29zIExvaXMgQmVybcO6ZGV6?= User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Jonathan Corbet CC: linux-kernel@vger.kernel.org Subject: Re: Question about using new request_threaded_irq References: <50CF361A.1030203@gmail.com> <20121217083759.0cbed418@lwn.net> In-Reply-To: <20121217083759.0cbed418@lwn.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I lot of thanks for you fast reply. It seem that i swap the mean of handler parameters, so i now see it correct. :). Excuse for my newbie question. handler is the primary handler, and if NULL a default primary handler is installed, and thread_fn is the thread handler. I'm a bit confusing because i see a outdated page that talks about this new IRQ API, but now i see that it's very outdated: http://lwn.net/Articles/302043/ Regards. El 17/12/2012 16:37, Jonathan Corbet escribió: > On Mon, 17 Dec 2012 16:11:22 +0100 > Marcos Lois Bermúdez wrote: > >> For my understand if i call for example: >> >> request_threaded_irq(irqmum, NULL, irq_handle, IRQF_TRIGGER_FALLING, >> DEVICE_NAME, priv); >> >> This seem to make a old Hard IRQ handler, and inside of this handler >> sleep APIs can't be used, but i see some SPI drivers that seem to >> register a IRQ of this form and make API calls that can sleep in the >> handler. > > Not quite. The prototype for request_threaded_irq() is: > > int request_threaded_irq(unsigned int irq, irq_handler_t handler, > irq_handler_t thread_fn, unsigned long irqflags, > const char *devname, void *dev_id) > > Note the presents of *two* handlers, called "handler" and "thread_fn". > The first, "handler", is called in interrupt context; it's job is usually > to quiet the device and return; it cannot sleep. If it's return value is > IRQ_WAKE_THREAD, the thread_fn() will be called in process context; it > *can* sleep. In the example you cite, there is no immediate handler, only > the thread_fn(); the call to a blocking function from within the > thread_fn() is correct. > > Hope that helps, > > jon > > Jonathan Corbet / LWN.net / corbet@lwn.net >