From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gleixner Subject: Re: Setting the priority of an IRQ thread Date: Wed, 17 Jun 2009 11:00:53 +0200 (CEST) Message-ID: References: <000001c9ee36$218cf3a0$a852c70a@dlh.st.com> <20090616182734.GD13048@pengutronix.de> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: linux-rt-users@vger.kernel.org To: Martin Shepherd Return-path: Received: from www.tglx.de ([62.245.132.106]:50033 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752293AbZFQJBD (ORCPT ); Wed, 17 Jun 2009 05:01:03 -0400 In-Reply-To: Sender: linux-rt-users-owner@vger.kernel.org List-ID: On Tue, 16 Jun 2009, Martin Shepherd wrote: > On Wed, 17 Jun 2009, Thomas Gleixner wrote: > > > It seems much more friendly and efficient for my driver to provide > > > applications with an ioctl that tells it to set the priority of its > > > IRQ thread. > > > > Wrong. That information is already available in sysfs and there is no > > reason to use an ioctl for that. > > Could you point out where please? Searching sysfs I see the following > two files that contain the IRQ numbers of two of the boards that my > driver handles: > > /bus/pci/drivers/accpcidio/0000:03:02.0/irq > /bus/pci/drivers/accpcidio/0000:03:03.0/irq > > However, I don't see how a user application could figure out which of > these corresponded to the board that it opened using a particular > device file. Only the device driver knows which device file is > associated with a given PCI device ID, and that isn't recorded in > sysfs. Errm, and how does udev figure out which device node to create for which device ? /sys/devices/pci0000:00/0000:00:1d.7/usb1/dev Thanks, tglx