Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753291Ab1BNLDr (ORCPT ); Mon, 14 Feb 2011 06:03:47 -0500 Received: from mail-fx0-f46.google.com ([209.85.161.46]:61192 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753002Ab1BNLDp (ORCPT ); Mon, 14 Feb 2011 06:03:45 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=FSZ/gafD51hbqYr9I3x0jit7nMdUWU059SvE4g4BSNRjGo5qJ6i57vbpMKA+SaqkCK nwhmqLu3tZ3aWq29oz6dd4QcjDUj0mEk5Q9uWAg5EpOJtUEljOiBQugMYTz01/CdHzXg kGHresaZAfUafp3W49++iZ21AIwnoEWcuexko= Date: Mon, 14 Feb 2011 12:03:39 +0100 From: Tejun Heo To: Dmitry Torokhov Cc: Andy Walls , linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, stoth@kernellabs.com Subject: Re: cx23885-input.c does in fact use a workqueue.... Message-ID: <20110214110339.GC18742@htj.dyndns.org> References: <1297647322.19186.61.camel@localhost> <20110214043355.GA28090@core.coreip.homeip.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110214043355.GA28090@core.coreip.homeip.net> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2448 Lines: 67 Hello, On Sun, Feb 13, 2011 at 08:33:55PM -0800, Dmitry Torokhov wrote: > > The cx23885 driver does in fact schedule work for IR input handling: > > > > Here's where it is scheduled for CX23888 chips: > > > > http://git.linuxtv.org/media_tree.git?a=blob;f=drivers/media/video/cx23885/cx23885-ir.c;h=7125247dd25558678c823ee3262675570c9aa630;hb=HEAD#l76 > > > > Here's where it is scheduled for CX23885 chips: > > > > http://git.linuxtv.org/media_tree.git?a=blob;f=drivers/media/video/cx23885/cx23885-core.c;h=359882419b7f588b7c698dbcfb6a39ddb1603301;hb=HEAD#l1861 Ah, sorry about missing those. > > The two different chips are handled slightly differently because > > > > a. the CX23888 IR unit is accessable via a PCI register block. The IR > > IRQ can be acknowledged with direct PCI register accesses in an > > interrupt context, and the IR pulse FIFO serviced later in a workqueue > > context. > > > > b. the CX23885 IR unit is accessed over an I2C bus. The CX23885 A/V IRQ > > has to be masked in an interrupt context (with PCI registers accesses). > > Then the CX23885 A/V unit's IR IRQ is ack'ed over I2C in a workqueue > > context and the IR pulse FIFO is also serviced over I2C in a workqueue > > context. > > > > > > So what should be done about the flush_scheduled_work()? I think it > > belongs there. > > > > Convert to using threaded irq? Or 1. Just flush the work items explicitly using flush_work_sync(). 2. Create a dedicated workqueue to serve as flushing domain. The first would look like the following. Does this look correct? Thanks. diff --git a/drivers/media/video/cx23885/cx23885-input.c b/drivers/media/video/cx23885/cx23885-input.c index 199b996..e27cedb 100644 --- a/drivers/media/video/cx23885/cx23885-input.c +++ b/drivers/media/video/cx23885/cx23885-input.c @@ -229,6 +229,9 @@ static void cx23885_input_ir_stop(struct cx23885_dev *dev) v4l2_subdev_call(dev->sd_ir, ir, rx_s_parameters, ¶ms); v4l2_subdev_call(dev->sd_ir, ir, rx_g_parameters, ¶ms); } + flush_work_sync(&dev->cx25840_work); + flush_work_sync(&dev->ir_rx_work); + flush_work_sync(&dev->ir_tx_work); } static void cx23885_input_ir_close(struct rc_dev *rc) -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/