Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752354AbbLUWqg (ORCPT ); Mon, 21 Dec 2015 17:46:36 -0500 Received: from mail-oi0-f47.google.com ([209.85.218.47]:33781 "EHLO mail-oi0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752303AbbLUWqf (ORCPT ); Mon, 21 Dec 2015 17:46:35 -0500 MIME-Version: 1.0 In-Reply-To: <56783CE4.8080405@redhat.com> References: <56783CE4.8080405@redhat.com> From: Andy Lutomirski Date: Mon, 21 Dec 2015 14:46:15 -0800 Message-ID: Subject: Re: firmware_class warnings on resume To: Laura Abbott Cc: Ming Lei , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1698 Lines: 51 On Mon, Dec 21, 2015 at 9:54 AM, Laura Abbott wrote: > On 12/20/2015 04:20 AM, Andy Lutomirski wrote: >> >> I hit this warning fairly frequently when resuming 4.4-rc5: >> >> ret = usermodehelper_read_trylock(); >> if (WARN_ON(ret)) { >> dev_err(device, "firmware: %s will not be loaded\n", >> name); >> goto out; >> } >> >> It seems like it could be improved in two ways fairly easily: >> >> 1. Shouldn't firmware_class try the direct load before trying to get >> the usermodehelper lock? >> >> 2. Why is the !NOWAIT case doing a trylock? That seems wrong. >> >> --Andy >> > > I saw the same warning coming from the bluetooth stack, see the thread > http://article.gmane.org/gmane.linux.kernel/1950940 and > http://article.gmane.org/gmane.linux.kernel/1940130. > At least in the bluetooth case, the conclusion was the firmware request > should not be happening at that point in time and the reset_resume function > should be implemented instead. I put that work aside and haven't picked > it up again. That's exactly the issue I'm seeing, and I think you're right. Still, I think the firmware_class code is wrong, too. If it wants to warn, it should warn that firmware was requested too early in resume. Using trylock as an excuse to fail a firmware load seems completely bogus to me. > > Thanks, > Laura -- Andy Lutomirski AMA Capital Management, LLC -- 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/