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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 48D6DC46CA1 for ; Mon, 18 Sep 2023 03:49:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230142AbjIRDss (ORCPT ); Sun, 17 Sep 2023 23:48:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57574 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230360AbjIRDs2 (ORCPT ); Sun, 17 Sep 2023 23:48:28 -0400 Received: from muru.com (muru.com [72.249.23.125]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id CAA5F10E; Sun, 17 Sep 2023 20:48:21 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id C00A080BF; Mon, 18 Sep 2023 03:48:20 +0000 (UTC) Date: Mon, 18 Sep 2023 06:48:19 +0300 From: Tony Lindgren To: "H. Nikolaus Schaller" Cc: Tomi Valkeinen , Laurent Pinchart , Sebastian Reichel , dri-devel@lists.freedesktop.org, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org, Daniel Vetter , David Airlie Subject: Re: [PATCH] drm/omap: dsi: Fix deferred probe warnings Message-ID: <20230918034819.GO5285@atomide.com> References: <20230412073954.20601-1-tony@atomide.com> <9daacd2f-0dbf-dddc-9403-b802447896a2@ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org * H. Nikolaus Schaller [230916 12:50]: > Hi Tomi and Tony, > > > Am 13.09.2023 um 13:59 schrieb Tomi Valkeinen : > > > > On 12/04/2023 10:39, Tony Lindgren wrote: > >> We may not have dsi->dsidev initialized during probe, and that can > >> lead into various dsi related warnings as omap_dsi_host_detach() gets > >> called with dsi->dsidev set to NULL. > >> The warnings can be "Fixed dependency cycle(s)" followed by a > >> WARNING: CPU: 0 PID: 787 at drivers/gpu/drm/omapdrm/dss/dsi.c:4414. > >> Let's fix the warnings by checking for a valid dsi->dsidev. > >> Signed-off-by: Tony Lindgren > >> --- > >> drivers/gpu/drm/omapdrm/dss/dsi.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> diff --git a/drivers/gpu/drm/omapdrm/dss/dsi.c b/drivers/gpu/drm/omapdrm/dss/dsi.c > >> --- a/drivers/gpu/drm/omapdrm/dss/dsi.c > >> +++ b/drivers/gpu/drm/omapdrm/dss/dsi.c > >> @@ -4411,7 +4411,7 @@ static int omap_dsi_host_detach(struct mipi_dsi_host *host, > >> { > >> struct dsi_data *dsi = host_to_omap(host); > >> - if (WARN_ON(dsi->dsidev != client)) > >> + if (dsi->dsidev && WARN_ON(dsi->dsidev != client)) > >> return -EINVAL; > >> cancel_delayed_work_sync(&dsi->dsi_disable_work); > > > > Shouldn't this rather be > > > > if (!dsi->dsidev) > > return 0; > > > > before the if (WARN_ON(dsi->dsidev != client)) line? > > Yes you are right. We have a different variant in our Pyra kernel: > > What we currently have in our Pyra tree is: https://git.goldelico.com/?p=letux-kernel.git;a=commitdiff;h=5bf7bd64eec1eb924e794e8d6600919f0dae8c5a;hp=27a0cd6263194d1465e9c53293d35f8c8c988f9d > > struct dsi_data *dsi = host_to_omap(host); > > - if (WARN_ON(dsi->dsidev != client)) > +printk("%s\n", __func__); > + > + if (!dsi->dsidev || WARN_ON(dsi->dsidev != client)) > return -EINVAL; > > cancel_delayed_work_sync(&dsi->dsi_disable_work); > > > > > If dsi->dsidev is NULL, then attach hasn't been called, and we shouldn't do anything in the detach callback either. > > > > With your change we'll end up doing all the work in the detach callback, without ever doing their counterpart in the attach side. > > If useful, I can post above mentioned patch (without printk). Sounds good to me. Thanks, Tony