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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 13B38C43441 for ; Thu, 29 Nov 2018 15:19:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D73FD20868 for ; Thu, 29 Nov 2018 15:19:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D73FD20868 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com 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 S1728683AbeK3CZO (ORCPT ); Thu, 29 Nov 2018 21:25:14 -0500 Received: from mga02.intel.com ([134.134.136.20]:17860 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728128AbeK3CZN (ORCPT ); Thu, 29 Nov 2018 21:25:13 -0500 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 29 Nov 2018 07:19:31 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,295,1539673200"; d="scan'208";a="96787606" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.174]) by orsmga008.jf.intel.com with SMTP; 29 Nov 2018 07:19:29 -0800 Received: by stinkbox (sSMTP sendmail emulation); Thu, 29 Nov 2018 17:19:28 +0200 Date: Thu, 29 Nov 2018 17:19:28 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Ahsan Hussain Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: drm: understanding the kernel warning during drm_vblank_cleanup() Message-ID: <20181129151928.GM9144@intel.com> References: <6198455d-59b4-c4b0-94c1-6e0d460f2451@mentor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <6198455d-59b4-c4b0-94c1-6e0d460f2451@mentor.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 Thu, Nov 29, 2018 at 07:30:45PM +0500, Ahsan Hussain wrote: > Hi folks, > > I'm new to DRM and trying to understand the warning in > drivers/gpu/drm/drm_vblank.c during drm_vblank_cleanup(). > > WARN_ON(READ_ONCE(vblank->enabled) && >     drm_core_check_feature(dev, DRIVER_MODESET)); > > Is the drm driver responsible for making sure that !(vblank->enabled) in > the .unbind operation, or is this something related to userspace? What > does the warning signify? Git history did not help here at all. It signifies you haven't cleaned up things properly. Usually what you would do is call drm_atomic_helper_shutdown() which will also end up turnng vblank interrupts off, assuming you use drm_vblank_on()/off() properly. -- Ville Syrjälä Intel