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 EFF62C7619A for ; Wed, 12 Apr 2023 08:56:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231326AbjDLI4P (ORCPT ); Wed, 12 Apr 2023 04:56:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231461AbjDLI4M (ORCPT ); Wed, 12 Apr 2023 04:56:12 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27A0D9EDE; Wed, 12 Apr 2023 01:55:55 -0700 (PDT) Received: from [192.168.88.20] (91-154-35-171.elisa-laajakaista.fi [91.154.35.171]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 9A91E616E; Wed, 12 Apr 2023 10:55:36 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1681289737; bh=UDmQ7tdOotgFk5t4ad0iJfZyoWPgoUIsI0VIhJnxXf0=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Q+TYV5v67df4OrQnVbqUVMf8xRBj/90aGqKD713V8X8PRiI9ynollZUZg6ilFukM9 vuqxAWUhJBmUyUK5Xcwp1bVUfxUxdRlWFi4PhRLk50PMGDJxHyk1HKjWF1quCwSKNh aR8GsekZvyDlCs17zh97oufICfEBn5B+vZIaB4+w= Message-ID: <2bf56c04-733b-24a5-a344-166a94cd51f7@ideasonboard.com> Date: Wed, 12 Apr 2023 11:55:34 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [PATCH] drm/omap: dsi: Fix deferred probe warnings To: Laurent Pinchart , Tony Lindgren Cc: David Airlie , Daniel Vetter , Sebastian Reichel , dri-devel@lists.freedesktop.org, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org References: <20230412073954.20601-1-tony@atomide.com> <20230412085044.GP11253@pendragon.ideasonboard.com> Content-Language: en-US From: Tomi Valkeinen In-Reply-To: <20230412085044.GP11253@pendragon.ideasonboard.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Tomi >> 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); >