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 F21E6C433FE for ; Sun, 3 Oct 2021 13:25:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D1E9561B30 for ; Sun, 3 Oct 2021 13:25:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230207AbhJCN1H (ORCPT ); Sun, 3 Oct 2021 09:27:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53754 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230050AbhJCN1G (ORCPT ); Sun, 3 Oct 2021 09:27:06 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0FBEFC0613EC; Sun, 3 Oct 2021 06:25:19 -0700 (PDT) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 0F2ADA2A; Sun, 3 Oct 2021 15:25:14 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1633267514; bh=VHWbPfGiA5vgTAu1+k5AM/WGLi1c7AUlzQbdWY3enhc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=h/2eYjwJbH2EhjYD40qxfbcEgYr3mE2IAAas4v5feH+XAkkT1BgxIkzYa06DtV8ZJ EGzSpMCGvRfSWCjwZLJzUC8o7X3Bf6J0UPkB/gHZWzl2XGBTtdBn6f67BRJU7V8OWE df/2bykLM9Wcuj02kfnm0rlzKLBpNTFJPdjZTaAU= Date: Sun, 3 Oct 2021 16:25:09 +0300 From: Laurent Pinchart To: Maxime Ripard Cc: Andrzej Hajda , Sam Ravnborg , Daniel Vetter , David Airlie , Jonas Karlman , Thierry Reding , Maarten Lankhorst , Thomas Zimmermann , Neil Armstrong , Robert Foss , Jernej Skrabec , Sean Paul , freedreno@lists.freedesktop.org, Kyungmin Park , linux-kernel@vger.kernel.org, Xinliang Liu , Seung-Woo Kim , Tian Tao , Inki Dae , linux-samsung-soc@vger.kernel.org, linux-arm-msm@vger.kernel.org, Rob Clark , dri-devel@lists.freedesktop.org, John Stultz , Chen Feng , Xinwei Kong , Joonyoung Shim , Kieran Bingham Subject: Re: [PATCH v4 00/24] drm/bridge: Make panel and bridge probe order consistent Message-ID: References: <20210910101218.1632297-1-maxime@cerno.tech> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org Hi Maxime, On Thu, Sep 30, 2021 at 12:56:02AM +0300, Laurent Pinchart wrote: > On Fri, Sep 10, 2021 at 12:11:54PM +0200, Maxime Ripard wrote: > > Hi, > > > > We've encountered an issue with the RaspberryPi DSI panel that prevented the > > whole display driver from probing. > > > > The issue is described in detail in the commit 7213246a803f ("drm/vc4: dsi: > > Only register our component once a DSI device is attached"), but the basic idea > > is that since the panel is probed through i2c, there's no synchronization > > between its probe and the registration of the MIPI-DSI host it's attached to. > > > > We initially moved the component framework registration to the MIPI-DSI Host > > attach hook to make sure we register our component only when we have a DSI > > device attached to our MIPI-DSI host, and then use lookup our DSI device in our > > bind hook. > > > > However, all the DSI bridges controlled through i2c are only registering their > > associated DSI device in their bridge attach hook, meaning with our change > > above, we never got that far, and therefore ended up in the same situation than > > the one we were trying to fix for panels. > > > > The best practice to avoid those issues is to register its functions only after > > all its dependencies are live. We also shouldn't wait any longer than we should > > to play nice with the other components that are waiting for us, so in our case > > that would mean moving the DSI device registration to the bridge probe. > > > > I also had a look at all the DSI hosts, and it seems that exynos, kirin and msm > > would be affected by this and wouldn't probe anymore after those changes. > > Exynos and kirin seems to be simple enough for a mechanical change (that still > > requires to be tested), but the changes in msm seemed to be far more important > > and I wasn't confortable doing them. > > > > Let me know what you think, > > I've tested this series on my RPi CM4-based board, and there's a clear > improvement: the sn65dsi83 now probes successfully ! > > The downside is that I can now look at a panel that desperately refuses > to display anything. That's a separate issue, but it prevents me from > telling whether this series introduces regressions :-S I'll try to debug > that separately. I managed to (partly) fix that issue with a few backports from the RPi kernel, making me confident enough to say Tested-by: Laurent Pinchart for drivers/gpu/drm/bridge/ti-sn65dsi83.c drivers/gpu/drm/drm_bridge.c drivers/gpu/drm/drm_mipi_dsi.c include/drm/drm_mipi_dsi.h > Also, Kieran, would you be able to test this with the SN65DSI86 ? > > > --- > > > > Changes from v3: > > - Converted exynos and kirin > > - Converted all the affected bridge drivers > > - Reworded the documentation a bit > > > > Changes from v2: > > - Changed the approach as suggested by Andrzej, and aligned the bridge on the > > panel this time. > > - Fixed some typos > > > > Changes from v1: > > - Change the name of drm_of_get_next function to drm_of_get_bridge > > - Mention the revert of 87154ff86bf6 and squash the two patches that were > > reverting that commit > > - Add some documentation > > - Make drm_panel_attach and _detach succeed when no callback is there > > > > Maxime Ripard (24): > > drm/bridge: Add documentation sections > > drm/bridge: Document the probe issue with MIPI-DSI bridges > > drm/mipi-dsi: Create devm device registration > > drm/mipi-dsi: Create devm device attachment > > drm/bridge: adv7533: Switch to devm MIPI-DSI helpers > > drm/bridge: adv7511: Register and attach our DSI device at probe > > drm/bridge: anx7625: Switch to devm MIPI-DSI helpers > > drm/bridge: anx7625: Register and attach our DSI device at probe > > drm/bridge: lt8912b: Switch to devm MIPI-DSI helpers > > drm/bridge: lt8912b: Register and attach our DSI device at probe > > drm/bridge: lt9611: Switch to devm MIPI-DSI helpers > > drm/bridge: lt9611: Register and attach our DSI device at probe > > drm/bridge: lt9611uxc: Switch to devm MIPI-DSI helpers > > drm/bridge: lt9611uxc: Register and attach our DSI device at probe > > drm/bridge: ps8640: Switch to devm MIPI-DSI helpers > > drm/bridge: ps8640: Register and attach our DSI device at probe > > drm/bridge: sn65dsi83: Switch to devm MIPI-DSI helpers > > drm/bridge: sn65dsi83: Register and attach our DSI device at probe > > drm/bridge: sn65dsi86: Switch to devm MIPI-DSI helpers > > drm/bridge: sn65dsi86: Register and attach our DSI device at probe > > drm/bridge: tc358775: Switch to devm MIPI-DSI helpers > > drm/bridge: tc358775: Register and attach our DSI device at probe > > drm/kirin: dsi: Adjust probe order > > drm/exynos: dsi: Adjust probe order > > > > Documentation/gpu/drm-kms-helpers.rst | 12 +++ > > drivers/gpu/drm/bridge/adv7511/adv7511.h | 1 - > > drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 15 ++- > > drivers/gpu/drm/bridge/adv7511/adv7533.c | 20 +--- > > drivers/gpu/drm/bridge/analogix/anx7625.c | 40 ++++---- > > drivers/gpu/drm/bridge/lontium-lt8912b.c | 31 ++---- > > drivers/gpu/drm/bridge/lontium-lt9611.c | 62 +++++------- > > drivers/gpu/drm/bridge/lontium-lt9611uxc.c | 65 +++++------- > > drivers/gpu/drm/bridge/parade-ps8640.c | 101 ++++++++++--------- > > drivers/gpu/drm/bridge/tc358775.c | 50 +++++---- > > drivers/gpu/drm/bridge/ti-sn65dsi83.c | 86 ++++++++-------- > > drivers/gpu/drm/bridge/ti-sn65dsi86.c | 94 ++++++++--------- > > drivers/gpu/drm/drm_bridge.c | 69 ++++++++++++- > > drivers/gpu/drm/drm_mipi_dsi.c | 81 +++++++++++++++ > > drivers/gpu/drm/exynos/exynos_drm_dsi.c | 19 ++-- > > drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c | 27 +++-- > > include/drm/drm_mipi_dsi.h | 4 + > > 17 files changed, 460 insertions(+), 317 deletions(-) -- Regards, Laurent Pinchart