Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751601Ab3EIH0K (ORCPT ); Thu, 9 May 2013 03:26:10 -0400 Received: from cantor2.suse.de ([195.135.220.15]:32859 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750842Ab3EIH0I (ORCPT ); Thu, 9 May 2013 03:26:08 -0400 Date: Thu, 09 May 2013 09:26:06 +0200 Message-ID: From: Takashi Iwai To: Kay Sievers Cc: Ming Lei , linux-kernel@vger.kernel.org, Greg Kroah-Hartman Subject: Re: [PATCH 0/3] firmware: Fix usermodehelper deadlock at shutdown In-Reply-To: References: <1367996197-32748-1-git-send-email-tiwai@suse.de> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/24.2 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2471 Lines: 59 At Wed, 8 May 2013 20:46:43 +0200, Kay Sievers wrote: > > On Wed, May 8, 2013 at 6:26 PM, Takashi Iwai wrote: > > At Thu, 9 May 2013 00:07:17 +0800, > > Ming Lei wrote: > > >> On Wed, May 8, 2013 at 2:56 PM, Takashi Iwai wrote: > >> > Hi, > >> > > >> > this is a series of patches for the issue we faced in the firmware > >> > loader code during debugging the problem with dell_rbu driver with > >> > 3.9 kernel. > >> > > >> > The original problem was that the shutdown gets stuck when DELL BIOS > >> > update is performed. This turned out to be a problem in the firmware > >> > loader. Although the reason of dell_rbu driver breakage is still > >> > >> Sorry, from these patchset, I can't see why it is a problem in firmware. > >> > >> > unclear, we should fix the firmware loader side, at least, not to > >> > stall during shutdown. > >> > >> Firstly you need to describe what/why is the stall? In fact, firmware > >> loading can't stall forever and it will timeout, but the current 60sec > >> timeout might be too long. > > > > The timeout check is activated only when uevent flag is set, and > > dell_rbu driver doesn't set it explicitly (because it's not supposed > > to be handled via udev or whatever). > > These use the firmware loader not in the way the interface was intended: > drivers/misc/lattice-ecp3-config.c > drivers/firmware/dell_rbu.c > > They just use the mechanism without any of the usual userspace setup. > It's really a nasty hack to hijack the interface that way. > > The commit 6e3eaab02028c4087a92711b20abb9e72cc803a7 is a pretty broken > idea to start with. If something triggers uevents during runtime which > is not uncommon, these on-demand silently created firmware devices > would get really confused and race against the udev firmware loader > which cancels the events. > > As if the userspace firmware loading in general wasn't a bad enough > idea already. :) Luckily there are only few users, so conversion of such known drivers should be easy. But the major question is whether we are allowed to drop the non-hotplug f/w loading right now after years. It means a clear user-space breakage, and we don't want it as much as possible. Takashi -- 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/