Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 27 Feb 2002 03:27:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 27 Feb 2002 03:27:09 -0500 Received: from ns1.alcove-solutions.com ([212.155.209.139]:50103 "EHLO smtp-out.fr.alcove.com") by vger.kernel.org with ESMTP id ; Wed, 27 Feb 2002 03:26:51 -0500 Date: Wed, 27 Feb 2002 09:26:42 +0100 From: Stelian Pop To: Pete Zaitcev Cc: linux-kernel@vger.kernel.org Subject: Re: PCI driver in userspace Message-ID: <20020227082642.GA19173@come.alcove-fr> Reply-To: Stelian Pop In-Reply-To:

<200202270052.g1R0qdK11879@devserv.devel.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200202270052.g1R0qdK11879@devserv.devel.redhat.com> User-Agent: Mutt/1.3.25i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 26, 2002 at 07:52:39PM -0500, Pete Zaitcev wrote: [Interrupts in userspace...] > >> Although I dont know if this is a good idea in the first place. > > > > I think it depends on the interrupt frequency, and other things. > > > This is why purely > user level interrupts are IMPOSSIBLE (regardless of interrupt > frequency). [...] > 2. Write a small driver that deactivates interrupts and queues > interrupt events (with SIGIO and some other means). This is what I meant too, and I was talking about the interrupt frequency because if there are too many IT, continuous polling might be more efficient than interrupt handling with the kernel driver + userspace signal sending. > Very many people are psychologically afraid of drivers > (even though it's quite simple), and they wank those userspace > approaches, until they hit some brick wall (interrupts being > most common). By that time they invest so much into their code > that they are loth to abandon broken userland drivers and > start grappling about desperately for a way out. It depends on the driver. If moving _all_ the driver in kernelspace involves putting policy and other stuff into the kernel, then no. Stelian. -- Stelian Pop Alcove - http://www.alcove.com - 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/