Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932185AbWEHO04 (ORCPT ); Mon, 8 May 2006 10:26:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932187AbWEHO04 (ORCPT ); Mon, 8 May 2006 10:26:56 -0400 Received: from smtpout.mac.com ([17.250.248.185]:32200 "EHLO smtpout.mac.com") by vger.kernel.org with ESMTP id S932185AbWEHO0z (ORCPT ); Mon, 8 May 2006 10:26:55 -0400 In-Reply-To: <20060507131201.GC5765@ucw.cz> References: <1146784923.4581.3.camel@localhost.localdomain> <445BA584.40309@us.ibm.com> <9e4733910605051314jb681476y4b2863918dfae1f8@mail.gmail.com> <20060505202603.GB6413@kroah.com> <9e4733910605051335h7a98670ie8102666bbc4d7cd@mail.gmail.com> <20060505210614.GB7365@kroah.com> <9e4733910605051415o48fddbafpf0f8b096f971e482@mail.gmail.com> <20060505222738.GA8985@kroah.com> <9e4733910605051705j755ad61dm1c07c66c2c24c525@mail.gmail.com> <21d7e9970605051857l4415a04ai7d1b1f886bb01cee@mail.gmail.com> <20060507131201.GC5765@ucw.cz> Mime-Version: 1.0 (Apple Message framework v746.3) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: Cc: Dave Airlie , Jon Smirl , Greg KH , Ian Romanick , Dave Airlie , Arjan van de Ven , linux-kernel@vger.kernel.org Content-Transfer-Encoding: 7bit From: Kyle Moffett Subject: Re: Add a "enable" sysfs attribute to the pci devices to allow userspace (Xorg) to enable devices without doing foul direct access Date: Mon, 8 May 2006 10:26:52 -0400 To: Pavel Machek X-Mailer: Apple Mail (2.746.3) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1538 Lines: 32 On May 7, 2006, at 09:12:01, Pavel Machek wrote: >>> It has everything to do with the 'enable' file. The 'enable' file >>> lets you change the state of the hardware without an ownership >>> mechanism. Other device users will not be notified of the state >>> change. Since the other users can't be sure of the state of the >>> hardware when they are activated, they will have to reload their >>> state into the hardware on every activation. >> >> you seem to miss the fact that this can be done now without the >> enable flag, setpci can be used to disable the BARs, again the >> enable flag doesn't change that.... > > ...well, when you launch setpci, you are firmly in 'unsupported' > land. While 'enable' sounds like something where users expect it > to be supported. *Especially* since there are a number of users (including myself) who have tendencies to go wandering around sysfs tinkering with the available values. Not having seen this thread, I would have had no problem doing "echo -n 0 >enable" on some device thinking that it was a fairly standard way to turn off the power to my soundcard when I'm not using it, and likely result in a kernel panic because I suddenly disabled the BARs on the device out from under the driver. Cheers, Kyle Moffett - 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/