From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753045Ab3BRLzz (ORCPT ); Mon, 18 Feb 2013 06:55:55 -0500 Received: from plane.gmane.org ([80.91.229.3]:38505 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751852Ab3BRLzy (ORCPT ); Mon, 18 Feb 2013 06:55:54 -0500 X-Injected-Via-Gmane: http://gmane.org/ To: linux-kernel@vger.kernel.org From: el es Subject: Re: Stupid user with user-space questions, matrix LED driving with user space code only. Date: Mon, 18 Feb 2013 11:55:38 +0000 (UTC) Message-ID: References: <1361025476.4271.36.camel@jonspc> <1361082134.16206.24.camel@anish-Inspiron-N5050> <1361111844.14757.29.camel@jonspc> <20130218020557.GA27667@kroah.com> <1361163968.29540.62.camel@jonspc> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: sea.gmane.org User-Agent: Loom/3.14 (http://gmane.org/) X-Loom-IP: 81.148.108.228 (Mozilla/5.0 (Windows NT 5.1; rv:18.0) Gecko/20100101 Firefox/18.0) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jonathan Andrews jonshouse.co.uk> writes: > > What about a yield alignment mechanism for user space. IE the process > calls the kernel with a request "schedule me first after a yeild" - then > the process at least has whatever the timer granularity is to do > something timing critical... add a flag to ignore or defer interrupts > and you have a semi 'hard-realtime' behaviour for user space, allowing > user space to grab small chunks of real time. Yes a nasty looking > facility for SMP intel servers but really useful for embedded. > Seems you have some (bad?) habits from embedded programming, you think Linux is FreeRTOS ;) Linux as such, as far as I read, is not a real-time OS, it will NOT do what you want in userspace, (maybe unless you build it with the RT patchset?) Better take the advice and go build a kernel driver for this display. Or use a small microcontroller that won't have the limitations. > Thanks, > Jon > > Lukasz