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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C0202E87835 for ; Tue, 3 Feb 2026 14:10:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Na/aLGpL+Vxzc1WLveA1WNpTsOu7ajYqZYVLJf09FO0=; b=3rCiwK/AWgSDdO4atfobB0QvLZ eXIsSY/bgaH+a/LIr0dLENrelLgnPJhR+4XjmDglM6mBH9kk1PtsRPTAi/3sanVe0606idopewa/n //Lc5kHIeD84mGE8HAX6SQk40EkblJ1CGV2tml3vdbcPjeYT2TsC8ETOqaWUDkBiKVycgtac5UtZ3 VoICWoVSa6O7EpbOYENeNcQ1IeXgNTU+EWAWD28XHkn19tgL5n0fyjfJP0SHZ7FbDVX6yU4fZQ4g8 NgGrf6qeflchZc8LdkHWu3YfZ92Ca0Qjm9sk88sD5tsyJp0SfuFi2qK633re5COYBZwdyh6R3kgxa PTyiFwvw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vnH6J-00000006jdf-2gIW; Tue, 03 Feb 2026 14:09:55 +0000 Received: from perceval.ideasonboard.com ([213.167.242.64]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vnH6H-00000006jco-21vD; Tue, 03 Feb 2026 14:09:55 +0000 Received: from killaraus.ideasonboard.com (2001-14ba-703d-e500--2a1.rev.dnainternet.fi [IPv6:2001:14ba:703d:e500::2a1]) by perceval.ideasonboard.com (Postfix) with UTF8SMTPSA id AA6CA5B2; Tue, 3 Feb 2026 15:09:05 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1770127745; bh=Rv0gnZrGTVnHq8ksG/uGGrkDZi1zIa4ztL46UEkonLU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QP1vaF/qoOoTBXHPASYDi3HJe2FmO+pobt2RlBUxJF0hAgilkmQ+sAxpCisOQR058 rAIBf/hU7mmVDZi2gn8Ik0+Yc/jrD75aLWjNNQRrF1W6XRBxbiGTYTsI4HjC/LdrFE s/P/zP/t+p4sFm/xjtW23cZZu9j6yFOfaUuQzi/0= Date: Tue, 3 Feb 2026 16:09:45 +0200 From: Laurent Pinchart To: Luca Ceresoli Cc: Damon Ding , andrzej.hajda@intel.com, neil.armstrong@linaro.org, rfoss@kernel.org, dmitry.baryshkov@oss.qualcomm.com, jonas@kwiboo.se, jernej.skrabec@gmail.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, simona@ffwll.ch, shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com, inki.dae@samsung.com, sw0312.kim@samsung.com, kyungmin.park@samsung.com, krzk@kernel.org, alim.akhtar@samsung.com, jingoohan1@gmail.com, p.zabel@pengutronix.de, hjc@rock-chips.com, heiko@sntech.de, andy.yan@rock-chips.com, dianders@chromium.org, m.szyprowski@samsung.com, jani.nikula@intel.com, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-rockchip@lists.infradead.org Subject: Re: [PATCH v8 05/18] drm/bridge: Move legacy bridge driver out of imx directory for multi-platform use Message-ID: <20260203140945.GC12013@killaraus> References: <20251217093321.3108939-1-damon.ding@rock-chips.com> <20251217093321.3108939-6-damon.ding@rock-chips.com> <7256ecf9-b10b-428c-a1a6-e35e80a686ed@rock-chips.com> <9e1da672-a52d-4ec3-a20a-fe6f8ca15496@rock-chips.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260203_060953_661862_D9E88E45 X-CRM114-Status: GOOD ( 36.16 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Feb 03, 2026 at 11:11:50AM +0100, Luca Ceresoli wrote: > On Tue Feb 3, 2026 at 2:31 AM CET, Damon Ding wrote: > > On 2/2/2026 10:54 AM, Damon Ding wrote: > >> On 1/31/2026 8:33 PM, Luca Ceresoli wrote: > >>> On Wed Dec 17, 2025 at 10:33 AM CET, Damon Ding wrote: > >>>> As suggested by Dmitry, the DRM legacy bridge driver can be pulled > >>>> out of imx/ subdir for multi-platform use. The driver is also renamed > >>>> to make it more generic and suitable for platforms other than i.MX. > >>>> > >>>> Signed-off-by: Damon Ding > >>>> Suggested-by: Dmitry Baryshkov > >>>> Tested-by: Marek Szyprowski > >>>> > >>>> --- > >>>> > >>>> Changes in v7: > >>>> - Rename legacy-bridge to of-display-mode-bridge. > >>>> - Remove unnecessary API drm_bridge_is_legacy(). > >>> > >>> ... > >>> > >>>> --- a/drivers/gpu/drm/bridge/Kconfig > >>>> +++ b/drivers/gpu/drm/bridge/Kconfig > >>>> @@ -244,6 +244,16 @@ config DRM_NXP_PTN3460 > >>>>       help > >>>>         NXP PTN3460 eDP-LVDS bridge chip driver. > >>>> > >>>> +config DRM_OF_DISPLAY_MODE_BRIDGE > >>>> +    tristate > >>>> +    depends on DRM_BRIDGE && OF > >>>> +    help > >>>> +      This is a DRM bridge implementation that uses > >>>> of_get_drm_display_mode > >>>> +      to acquire display mode. > >>>> + > >>>> +      Newer designs should not use this bridge and should use proper > >>>> panel > >>>> +      driver instead. > >>> > >>> "Newer designs should not use this bridge", but in patch 8 you are > >>> introducing a new use ot devm_drm_of_display_mode_bridge(). Shouldn't you > >>> instead "use proper panel driver instead" in patch 8? > >>> > >>> Can you point to the conversation where the converstaion where Dmitry > >>> suggested this change? Maybe it already contains the answer to my > >>> qustion. Also adding a link to that conversation in the commit message > >>> woule be useful. > >>> > >> > >> First of all, thanks for your reviews on this patch series. > >> > >> link: https://lore.kernel.org/all/ > >> xwenycscalzdlpuxytorbiyvej3k7pv3lhxwtadilxq65ipwsv@x5rxm53w5e22/ > >> > >> I think it may be a misleading issue caused by directly copying the > >> previous Kconfig description. Now that the new > >> devm_drm_of_display_mode_bridge() helper has been added, drivers using > >> the panel-bridge framework can rely on it to maintain compatibility with > >> legacy display mode parsing. > > Ah, I think I got the point: the mode description in device tree is legacy, > but the driver itself is not legacy and will be current until we need to > support legacy device tree. Correct? > > If that's correct, this patch looks OK to me with a new Kconfig help text. The devm_drm_of_display_mode_bridge() function needs documentation though, with a warning that tells it must not be used in new drivers. Catching new users in checkpatch.pl (or somewhere else) would be ideal. I would also not create a separate module for this and move the function to drm_bridge.c, but I don't mind that much if the consensus is that a separate module is better. > >> It would be better to update the comment as follows: > >> > >> This is a DRM bridge implementation that uses of_get_drm_display_mode to > >> acquire display mode. > >> > >> It exists for compatibility with legacy display mode parsing, in order > >> to conform to the panel-bridge framework. > >> > > > > Dmitry, what's you take on this? > > Dmitry's opinion would be much more relevant than mine. I don't know much > myself about this driver. -- Regards, Laurent Pinchart