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 CC7B2C433F5 for ; Wed, 29 Sep 2021 21:56:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B458361423 for ; Wed, 29 Sep 2021 21:56:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345002AbhI2V5s (ORCPT ); Wed, 29 Sep 2021 17:57:48 -0400 Received: from perceval.ideasonboard.com ([213.167.242.64]:42244 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344896AbhI2V5r (ORCPT ); Wed, 29 Sep 2021 17:57:47 -0400 Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 483D73F0; Wed, 29 Sep 2021 23:56:04 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1632952564; bh=4pXRQUyT1Eo/BIzo6mOjlkLuticVDm/Q4c6/I+IRuuQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VNZoEMLZ8jmhckO07m/ckQ+s1iZB6E98r4/r1Z/ooprZsn6AtcHjS9JXMgRaBlRaC 0b57gXYen78UHq8hYGODIgbSKj8Rq3Qi9g1ylhaq8NyLeratnlhx49jk+XqjUzbEaN qEftTB9XMwOStn5/8BAjipunX/zvpJukMF8Q7QtQ= Date: Thu, 30 Sep 2021 00:56:02 +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: <20210910101218.1632297-1-maxime@cerno.tech> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Hi Maxime, (CC'ing Kieran) 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. 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