From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 09DEAC43441 for ; Sat, 10 Nov 2018 18:26:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B975020892 for ; Sat, 10 Nov 2018 18:26:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="jC+EF8z2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B975020892 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727024AbeKKEMS (ORCPT ); Sat, 10 Nov 2018 23:12:18 -0500 Received: from mail.kernel.org ([198.145.29.99]:48800 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726352AbeKKEMS (ORCPT ); Sat, 10 Nov 2018 23:12:18 -0500 Received: from localhost (71-6-98-120.static-ip.telepacific.net [71.6.98.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 86B4220854; Sat, 10 Nov 2018 18:26:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541874382; bh=mx2HYjSCyy4jL++iBsNld7tp450VUBwYwbhx6mcqjGo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jC+EF8z2zVBTks9bAZHFRijog0faYGVMxdKIIvNCzq9RxYstMuiweWU4JEqjci7cg sr6/UrEwH0U1sb7RFxmAOjb6rwpPagXm3nDUjQLKLgn1B/xlx/PDuoDb+4nlI0V28D ZhBDTjzKAu7UbpWb4ceVxEe8HV6yU1U7CWxUkvSk= Date: Sat, 10 Nov 2018 10:26:22 -0800 From: Greg Kroah-Hartman To: Andy Shevchenko Cc: MyungJoo Ham , Chanwoo Choi , linux-usb@vger.kernel.org, Felipe Balbi , Guenter Roeck , Heikki Krogerus , Roger Quadros , linux-pm@vger.kernel.org, "Rafael J. Wysocki" , Sebastian Reichel , linux-omap@vger.kernel.org, Darren Hart , platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, Chen-Yu Tsai , Hans de Goede , Grant Likely , Peter Ujfalusi , Mark Brown , Andrzej Hajda Subject: Re: [PATCH v1 1/5] drivercore: Revert "deferral race condition fix" Message-ID: <20181110182622.GA32657@kroah.com> References: <20181110181101.24557-1-andriy.shevchenko@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181110181101.24557-1-andriy.shevchenko@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Nov 10, 2018 at 08:10:57PM +0200, Andy Shevchenko wrote: > Consider the following scenario. > > There are two independent devices coupled together by functional dependencies: > - USB OTG (dwc3-pci) > - extcon (tested with extcon-intel-mrfld, not yet in upstream) > > Each of the driver services a corresponding device is built as a module. In the > Buildroot environment the modules are probed by alphabetical ordering of their > modaliases. The latter comes to the case when USB OTG driver will be probed > first followed by extcon one. > > So, if the platform anticipates extcon device to be appeared, in the above case > we will get deferred probe of USB OTG, because of ordering. > > Now, a cherry on top of the cake, the deferred probing list contains > the only two modules, i.e. USB OTG and extcon. Due to above circumstances, > values in the local_trigger_count and deferred_trigger_count are not the same, > and thus provokes deferred probe triggering again and again. > > ... > [ 20.678332] platform dwc3.0.auto: Retrying from deferred list > [ 20.694743] platform dwc3.0.auto: Driver dwc3 requests probe deferral > [ 20.701254] platform dwc3.0.auto: Added to deferred list > [ 20.706620] platform dwc3.0.auto: driver_deferred_probe_add_trigger 1 2 > [ 20.713732] platform dwc3.0.auto: Retrying from deferred list > [ 20.730035] platform dwc3.0.auto: Driver dwc3 requests probe deferral > [ 20.736540] platform dwc3.0.auto: Added to deferred list > [ 20.741889] platform dwc3.0.auto: driver_deferred_probe_add_trigger 3 4 > [ 20.748991] platform dwc3.0.auto: Retrying from deferred list > [ 20.765416] platform dwc3.0.auto: Driver dwc3 requests probe deferral > [ 20.771914] platform dwc3.0.auto: Added to deferred list > [ 20.777279] platform dwc3.0.auto: driver_deferred_probe_add_trigger 5 6 > ... > > Deeper investigation shows the culprit commit 58b116bce136 > ("drivercore: deferral race condition fix") which was dedicated to fix some > other issue while bringing a regression. > > This reverts commit 58b116bce13612e5aa6fcd49ecbd4cf8bb59e835 for good until > we will have better solution. > > Cc: Grant Likely > Cc: Peter Ujfalusi > Cc: Greg Kroah-Hartman > Cc: Mark Brown > Cc: Felipe Balbi > Cc: Andrzej Hajda > Signed-off-by: Andy Shevchenko > --- > drivers/base/dd.c | 27 ++------------------------- > 1 file changed, 2 insertions(+), 25 deletions(-) Shouldn't there be a "Fixes:" line and cc: stable here? thanks, greg k-h