Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752478Ab3GHRve (ORCPT ); Mon, 8 Jul 2013 13:51:34 -0400 Received: from cantor2.suse.de ([195.135.220.15]:40954 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751665Ab3GHRvd (ORCPT ); Mon, 8 Jul 2013 13:51:33 -0400 Date: Mon, 08 Jul 2013 19:52:50 +0200 Message-ID: From: Takashi Iwai To: Greg KH Cc: Dave Jones , Ming Lei , Linux Kernel Mailing List Subject: Re: dell_rbu: Select CONFIG_FW_LOADER_USER_HELPER explicitly In-Reply-To: <20130708164933.GB12670@kroah.com> References: <20130702192749.A2E7E660D9B@gitolite.kernel.org> <20130706221401.GA3652@redhat.com> <20130706223003.GA10697@kroah.com> <20130708164933.GB12670@kroah.com> 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: 2138 Lines: 50 At Mon, 8 Jul 2013 09:49:33 -0700, Greg KH wrote: > > On Mon, Jul 08, 2013 at 11:05:20AM +0200, Takashi Iwai wrote: > > The reason is that dell_rbu driver requires it. Without the kconfig > > option, this driver won't work at all. So, it's a right fix for > > dell_rbu. > > > > AFAIK, the consensus in the kernel side is that this too long fw > > loading time is basically a regression of user-space (udev or > > whatever). There is no change in the kernel behavior. The problem > > must exist even with the older kernels. > > > > But, looking at the development, we can't expect that udev will be > > fixed soon, and this breakage persists already way too long. Maybe a > > better solution is to kill the fallback to udev for normal f/w loading > > (i.e. for distro kernels). > > I thought udev was already fixed for this issue, so why would a "modern" > distro need to worry about this? Hm, I expected Dave is using the udev "modern" enough. If it's about an old udev behavior, we don't have to care so much... > > The patch below is an untested quick hack. It adds a new Kconfig and > > a new function request_firmware_via_user_helper(). Distro kernels may > > set CONFIG_FW_LOADER_USER_HELPER_FALLBACK=n for avoiding 60 seconds > > stall for non-existing firmware file access -- as distributions know > > that the firmware files should be placed in the right path. > > > > Thoughts? > > There's no way we can just fix up the driver instead of doing this in > the firmware core? The problem is that this non-udev-hotplug firmware loading mechanism was introduced exactly for this driver. Thus, we can't change the driver (thus ABI) without breaking user-space. Though, there are only two users of this interface. So, once when the user-space side is fixed, we can easily fix the kernel side, too, e.g. rewrite these drivers without abusing firmware interface. 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/