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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 77919C433F5 for ; Tue, 12 Oct 2021 20:47:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 511BE60C4B for ; Tue, 12 Oct 2021 20:47:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235056AbhJLUtY (ORCPT ); Tue, 12 Oct 2021 16:49:24 -0400 Received: from honk.sigxcpu.org ([24.134.29.49]:38770 "EHLO honk.sigxcpu.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233709AbhJLUtT (ORCPT ); Tue, 12 Oct 2021 16:49:19 -0400 Received: from localhost (localhost [127.0.0.1]) by honk.sigxcpu.org (Postfix) with ESMTP id C704DFB03; Tue, 12 Oct 2021 22:47:15 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at honk.sigxcpu.org Received: from honk.sigxcpu.org ([127.0.0.1]) by localhost (honk.sigxcpu.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id VTm-C2K1n71u; Tue, 12 Oct 2021 22:47:14 +0200 (CEST) Date: Tue, 12 Oct 2021 22:47:12 +0200 From: Guido =?iso-8859-1?Q?G=FCnther?= To: Laurent Pinchart Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Jyri Sarha , Tomi Valkeinen , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] drm/bridge: Ignore -EPROBE_DEFER when bridge attach fails Message-ID: References: <00493cc61d1443dab1c131c46c5890f95f6f9b25.1634068657.git.agx@sigxcpu.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Laurent, On Tue, Oct 12, 2021 at 11:17:07PM +0300, Laurent Pinchart wrote: > Hi Guido, > > Thank you for the patch. > > On Tue, Oct 12, 2021 at 09:58:58PM +0200, Guido Günther wrote: > > Otherwise logs are filled with > > > > [drm:drm_bridge_attach] *ERROR* failed to attach bridge /soc@0/bus@30800000/mipi-dsi@30a0 0000 to encoder None-34: -517 > > > > when the bridge isn't ready yet. > > > > Fixes: fb8d617f8fd6 ("drm/bridge: Centralize error message when bridge attach fails") > > Signed-off-by: Guido Günther > > --- > > drivers/gpu/drm/drm_bridge.c | 11 ++++++----- > > 1 file changed, 6 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c > > index a8ed66751c2d..f0508e85ae98 100644 > > --- a/drivers/gpu/drm/drm_bridge.c > > +++ b/drivers/gpu/drm/drm_bridge.c > > @@ -227,14 +227,15 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge, > > bridge->encoder = NULL; > > list_del(&bridge->chain_node); > > > > + if (ret != -EPROBE_DEFER) { > > #ifdef CONFIG_OF > > - DRM_ERROR("failed to attach bridge %pOF to encoder %s: %d\n", > > - bridge->of_node, encoder->name, ret); > > + DRM_ERROR("failed to attach bridge %pOF to encoder %s: %d\n", > > + bridge->of_node, encoder->name, ret); > > #else > > - DRM_ERROR("failed to attach bridge to encoder %s: %d\n", > > - encoder->name, ret); > > + DRM_ERROR("failed to attach bridge to encoder %s: %d\n", > > + encoder->name, ret); > > #endif > > - > > + } > > This looks fine as such, but I'm concerned about the direction it's > taking. Ideally, probe deferral should happen at probe time, way before > the bridge is attached. Doing otherwise is a step in the wrong direction > in my opinion, and something we'll end up regretting when we'll feel the > pain it inflicts. The particular case I'm seeing this is the nwl driver probe deferrals if the panel bridge isn't ready (which needs a bunch of components (dsi, panel, backlight wrapped led, ...) and it probes fine later on so I wonder where you see the actual error cause? That downstream of the bridge isn't ready or that the display controller is already attaching the bridge? Cheers, -- Guido > > > return ret; > > } > > EXPORT_SYMBOL(drm_bridge_attach); > > -- > Regards, > > Laurent Pinchart >