Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753952AbbG3G7R (ORCPT ); Thu, 30 Jul 2015 02:59:17 -0400 Received: from mail-ig0-f182.google.com ([209.85.213.182]:34261 "EHLO mail-ig0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751288AbbG3G7P (ORCPT ); Thu, 30 Jul 2015 02:59:15 -0400 MIME-Version: 1.0 In-Reply-To: <87vbd29mm6.fsf@ashishki-desk.ger.corp.intel.com> References: <1436177344-16751-1-git-send-email-alexander.shishkin@linux.intel.com> <1436177344-16751-2-git-send-email-alexander.shishkin@linux.intel.com> <877fpjkseh.fsf@ashishki-desk.ger.corp.intel.com> <87vbd29mm6.fsf@ashishki-desk.ger.corp.intel.com> Date: Thu, 30 Jul 2015 14:59:14 +0800 Message-ID: Subject: Re: [PATCH v3 01/11] stm class: Introduce an abstraction for System Trace Module devices From: Chunyan Zhang To: Alexander Shishkin Cc: Greg Kroah-Hartman , "linux-kernel@vger.kernel.org" , Mathieu Poirier , peter.lachner@intel.com, norbert.schulz@intel.com, keven.boell@intel.com, yann.fouassier@intel.com, laurent.fert@intel.com, "linux-api@vger.kernel.org" , Chunyan Zhang , Mark Brown 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: 1989 Lines: 55 On Thu, Jul 30, 2015 at 2:37 PM, Alexander Shishkin wrote: > Chunyan Zhang writes: > >> Sure, I mean, the root reason of this problem is here ( i.e. >> "stm_core_up" was zero then): >> if (!stm_core_up) >> return -EPROBE_DEFER; >> >> Why it was zero? >> Because the function (i.e. stm_core_init() ) in which "stm_core_up" >> would be added one hasn't been executed at this moment. It would be >> executed on module_init stage for you this version of patch. > > Again, this is the indented behavior. > >> The reason of this warning is: >> After stm_probe() failed, clk_core_disable() would be called from >> amba_put_disable_pclk(), then WARN_ON() happened: >> if (WARN_ON(core->enable_count == 0)) >> return; >> >> I'm guessing the reason why "core->enable_count" was 0 at this moment is: >> I don't know who created a thread to process the >> amba_pm_runtime_suspend(), in which clk_core_disable() was already >> called, "core->enable_count" was, of course, cleared to zero then. >> And this thread run before amba_put_disable_pclk(pcdev) which is just >> the one called from amba_probe() after >> "->probe"(i.e. stm_probe in this case) returning a non-zero value. > > No, this is guesswork. In amba_probe(), clocks are enabled for the > drv->probe() and then disabled afterwards and that's where the refcount > ends up unbalanced, the probe is the culprit. > > I can debug your driver for you but you'll at least need to put the code > up somewhere so I can see it. The code has already been submitted like I said in the earlier emails, you may refer [1]. Thanks, Chunyan [1] https://lkml.org/lkml/2015/2/4/729 > > Regards, > -- > Alex > -- 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/