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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6A6D9C77B6E for ; Wed, 12 Apr 2023 08:59:19 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8BF4C10E688; Wed, 12 Apr 2023 08:59:18 +0000 (UTC) Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by gabe.freedesktop.org (Postfix) with ESMTPS id EB12D10E688 for ; Wed, 12 Apr 2023 08:59:16 +0000 (UTC) Received: from pendragon.ideasonboard.com (133-32-181-51.west.xps.vectant.ne.jp [133.32.181.51]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 7451C616E; Wed, 12 Apr 2023 10:59:13 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1681289954; bh=qV8JcF2r9ggW8P3RPvH7aMgjXjti7cuWwbusF0BQCNA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XmoOx7nivKW6v+Wl0gFefaJBdo9ADbBHoXVkp7mQTmja1swWG+AoRsa9RvTvDAfrx ceW1LKV83YTEavEbQV+NZFAfSs+ZMvKnb3aeYdCHEViH2XpSHAt89Cn8np/8DHbEoE CofEouaVdxDeG0dZCWIgA/l171AgTKmxgmUYTRAQ= Date: Wed, 12 Apr 2023 11:59:26 +0300 From: Laurent Pinchart To: Tomi Valkeinen Subject: Re: [PATCH] drm/omap: dsi: Fix deferred probe warnings Message-ID: <20230412085926.GR11253@pendragon.ideasonboard.com> References: <20230412073954.20601-1-tony@atomide.com> <20230412085044.GP11253@pendragon.ideasonboard.com> <2bf56c04-733b-24a5-a344-166a94cd51f7@ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <2bf56c04-733b-24a5-a344-166a94cd51f7@ideasonboard.com> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Tony Lindgren , Sebastian Reichel , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Wed, Apr 12, 2023 at 11:55:34AM +0300, Tomi Valkeinen wrote: > On 12/04/2023 11:50, Laurent Pinchart wrote: > > Hi Tony, > > > > Thank you for the patch. > > > > On Wed, Apr 12, 2023 at 10:39:53AM +0300, 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. > > > > How can this happen ? I assume .detach() can't be called without a > > priori successful call to .attach(), that that sets dsi->dsidev. > > I had a quick look, and the driver calls mipi_dsi_host_register() in > probe, and mipi_dsi_host_unregister() in remove. > > mipi_dsi_host_unregister() always calls mipi_dsi_detach(), but I don't > think mipi_dsi_host_register() always calls attach, which happens later > when the peripheral probes. Is this something that should be addressed in the DRM MIPI DSI helpers, to only detach after an attach ? > >> 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); -- Regards, Laurent Pinchart