From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754579AbaIPXjr (ORCPT ); Tue, 16 Sep 2014 19:39:47 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:55428 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754490AbaIPXjo (ORCPT ); Tue, 16 Sep 2014 19:39:44 -0400 Date: Tue, 16 Sep 2014 16:39:46 -0700 From: Darren Hart To: Frans Klaver , Paul Bolle Cc: Greg Kroah-Hartman , Corentin Chary , Rafael Wysocki , acpi4asus-user , platform-driver-x86 , linux-kernel@vger.kernel.org, linux-acpi , "H. Peter Anvin" Subject: Re: [PATCH 10/13] eeepc-laptop: compare proper return values in get_cpufv Message-ID: <20140916233946.GB18698@vmdeb7> References: <1410563212-31565-1-git-send-email-fransklaver@gmail.com> <1410563212-31565-11-git-send-email-fransklaver@gmail.com> <20140915214902.GB64909@vmdeb7> <20140915215125.GA21435@kroah.com> <20140915215527.GC7867@gmail.com> <20140916205247.GA6856@vmdeb7> <20140916211001.GA23674@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140916211001.GA23674@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 16, 2014 at 11:10:01PM +0200, Frans Klaver wrote: > On Tue, Sep 16, 2014 at 01:52:47PM -0700, Darren Hart wrote: > > On Tue, Sep 16, 2014 at 01:54:25PM +0200, Frans Klaver wrote: > > > On Mon, Sep 15, 2014 at 11:55 PM, Frans Klaver wrote: > > > > On Mon, Sep 15, 2014 at 02:51:25PM -0700, Greg Kroah-Hartman wrote: > > > >> On Mon, Sep 15, 2014 at 02:49:02PM -0700, Darren Hart wrote: > > > >> > > > > >> > This patch is fine as is. However, Greg has supported propogating the error code > > > >> > through to the sysfs interface (if I understand him correctly on an earlier post > > > >> > to this list). This would require an addition change to this patch would > > > >> > propogated the get_cpufv error code in show_available_cpuv(), show_cpuv(), and > > > >> > store_cpuv(). As it is, we return -ENODEV on any failure, where an ACPI call > > > >> > error should probably return -ENXIO as I understand it. > > > >> > > > >> I really have no idea at this point in time what to recommend. How > > > >> about just stick with what is happening today so that: > > > >> > > > >> > However, there was a rather famous change in error code handling in which pulse > > > >> > audio broke and Linus was very upset with one of his maintainers. > > > >> > > > >> That doesn't happen :) > > > > > > > > So if I interpret that correctly, we're dropping the last patch > > > > (ENODEV -> ENXIO) from the series? That's fine by me. As mentioned > > > > earlier, I already saw something else break because I returned ENXIO > > > > instead of ENODEV. > > > > > > > > Maybe it's a good idea to try and document the expected behavior > > > > somewhere, if even Greg isn't sure what to do. > > > > > > For good measure: > > > > > > v2 will not change the return values at the sysfs interface, meaning > > > we will always return -ENODEV on error. I am going to try to keep as > > > much internal functions propagating errors as possible though, unless > > > someone strongly disagrees. > > > > > > Thanks, > > > Frans > > > > I cornered Linus today and asked about this specifically. The policy is this: > > > > Don't change the sysfs return codes without good reason. A good reason could be > > a real bug or problem with the return codes. It could also be to consolidate > > error handling which makes things more uniform, etc. > > > > If this results in broken userspace, the maintainer will revert the change. > > Alright, that is basically what I was expecting it to be. As it happens, > this also means that we'll have to decide what to do about returning > -EIO/-ENODEV/rv in show_sys_acpi and store_sys_acpi. The latter was > changed by Paul Bolle's "eeepc-laptop: simplify parse_arg()". The return > value of these functions is propagated to the sysfs interface. Yes, that change to store_sys_acpi needs to be reverted. I don't think show_sys_acpi is actually changed in that patch. Paul, can you resend that patch with the store_sys_acpi() -EIO return restored? -- Darren Hart Intel Open Source Technology Center