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 D6073CA5501 for ; Wed, 13 Sep 2023 07:37:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233816AbjIMHiC (ORCPT ); Wed, 13 Sep 2023 03:38:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54682 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238597AbjIMHiB (ORCPT ); Wed, 13 Sep 2023 03:38:01 -0400 Received: from muru.com (muru.com [72.249.23.125]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id A34681727; Wed, 13 Sep 2023 00:37:57 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id E3D438088; Wed, 13 Sep 2023 07:37:56 +0000 (UTC) Date: Wed, 13 Sep 2023 10:37:55 +0300 From: Tony Lindgren To: Laurent Pinchart Cc: Tomi Valkeinen , David Airlie , Daniel Vetter , Sebastian Reichel , dri-devel@lists.freedesktop.org, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] drm/omap: dsi: Fix deferred probe warnings Message-ID: <20230913073755.GE5285@atomide.com> References: <20230412073954.20601-1-tony@atomide.com> <20230412085044.GP11253@pendragon.ideasonboard.com> <2bf56c04-733b-24a5-a344-166a94cd51f7@ideasonboard.com> <20230412085926.GR11253@pendragon.ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230412085926.GR11253@pendragon.ideasonboard.com> Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org * Laurent Pinchart [230412 11:59]: > 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 ? Tomi, any comments on detach after attach? Regards, Tony > > >> 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 >