From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5C91B2C0296; Tue, 3 Mar 2026 14:24:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.251.105.195 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772547900; cv=none; b=nXSyxrjf7t1r1c33itPkjHW61zrylrkQeEs9nnejf4IhiB+WU9xk3MPHygUNo1X7EtSCdqbQg7cgfPi4DLwBLg8A8CRUpwp0tzWUWXPezUr/vVFthNX/j9kU0Z7xIXhGpSsx6X5w5ATkj/q7mnXJs5wnSPjgKRQ9oakiVRGISRY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772547900; c=relaxed/simple; bh=Wuu0sJNWhS9l8RA8loMZGodMF057v2ZgnGI93IEHQH8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=CS6kd9vP5zglGWs/O1XnhodVK/k9SWLGMLmHBscBghZRnqQ4XFeGyQPeGK/VXeG7b7qsv63ILQaJxi2e+Y3EOEWHgET27QrjVYIFUy/GxKfRPmSzv0xsVjL4Cym4BJod1QqwdGhYrMerQ8eBrO5tN+HvkkNMsOler35nkr8veLw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b=LAKKkoLB; arc=none smtp.client-ip=148.251.105.195 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="LAKKkoLB" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1772547897; bh=Wuu0sJNWhS9l8RA8loMZGodMF057v2ZgnGI93IEHQH8=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=LAKKkoLBDxV7fhvW7PQbnxmgd+EEhNbbiZhMIXv3zudJUMUxwzojDI/8vl/gjIRCK KTmBe+bwNOUd+Ap3ntDXb6MR3sYa0QS1x4Rfrcaus8KXPpNZyuZBpGP57Lko1P3Apa kqSWmH0N8k4nBRk5D4HweaGTGLd6BWvRpz6Fql7yjdVunGI6CImaNvJy8N25cQomuP R41mlxjoa+SyjZUuGm6bDkLHGNq3kmBR+ah7mAjmIo240KUIhymLkTBzLEb1vUGbhH 7ljpQVo4NITw7KjLe1XNtCV0B/gtkI6y1YevzWozsQVp4w/Ms1K/F4nxlXkgOez76G 7sMaw+DhRA53g== Received: from [192.168.1.100] (2-237-20-237.ip236.fastwebnet.it [2.237.20.237]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: kholk11) by bali.collaboradmins.com (Postfix) with ESMTPSA id D4A9D17E03E5; Tue, 3 Mar 2026 15:24:56 +0100 (CET) Message-ID: <4b318ffd-13cb-435c-af1a-2896d0e6cadb@collabora.com> Date: Tue, 3 Mar 2026 15:24:56 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 5/6] drm/mediatek: dsi: Add compatible for mt8167-dsi To: =?UTF-8?B?Q0sgSHUgKOiDoeS/iuWFiSk=?= , "l.scorcia@gmail.com" , "krzk+dt@kernel.org" Cc: "robh@kernel.org" , =?UTF-8?B?Q2h1bmZlbmcgWXVuICjkupHmmKXls7Ap?= , "simona@ffwll.ch" , "tzimmermann@suse.de" , "mripard@kernel.org" , "linux-kernel@vger.kernel.org" , "linux-mediatek@lists.infradead.org" , "dri-devel@lists.freedesktop.org" , "chunkuang.hu@kernel.org" , "vkoul@kernel.org" , "devicetree@vger.kernel.org" , "linux-phy@lists.infradead.org" , "p.zabel@pengutronix.de" , "conor+dt@kernel.org" , "airlied@gmail.com" , "linux-arm-kernel@lists.infradead.org" , "maarten.lankhorst@linux.intel.com" , "matthias.bgg@gmail.com" , "neil.armstrong@linaro.org" References: <2fbf179c03c61f527e2583f9df4f97f6aaf3297a.1771863641.git.l.scorcia@gmail.com> From: AngeloGioacchino Del Regno Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Il 03/03/26 08:56, CK Hu (胡俊光) ha scritto: > On Wed, 2026-02-25 at 09:15 +0100, Luca Leonardo Scorcia wrote: >> External email : Please do not click links or open attachments until you have verified the sender or the content. >> >> >>>> The mt8167 DSI controller is fully compatible with the one found in >>>> mt2701. Device tree documentation is already present upstream. >>> >>> If mt8167 DSI is fully compatible with mt2701 DSI, I think the binding document and device tree should be modified. >>> In device tree, >>> >>> compatible = "mediatek,mt8167-dsi", "mediatek,mt2701-dsi"; >>> >>> And this patch is not necessary. >> >> Hi, if I understand your review correctly that's what v2 [1] of this >> patch did, but the change was rejected during review. >> >> As far as I can see there is no win-win solution here. This tricky >> situation derives from the fact that in last year's submissions the >> change was only partially merged - the bindings went upstream while >> the driver did not, and now we have to work around this. In v3 I tried >> to address the issue by actually implementing what the binding >> document says. >> I'll be happy to resubmit v4 but I need to know what's the consensus here. > > You mean Krzysztof's comment? > He has two comment. > The first is 'remove'. You actually not remove "mediatek,mt8167-dsi". You change it. > The second is about fallback. I'm also not sure why he says it's NAK. Also a bad wording? > After Angelo's comment, Krzysztof does not response. > I also do not know what Krzysztof think. > I agree with Angelo. Single "mediatek,mt8167-dsi" does not reflect the hardware compatible but fallback does. > Maybe describe more information (hardware) to Krzysztof, and ask what's the better way to do. > First of all: I would be happy with having compatible = "mediatek,mt8167-dsi", "mediatek,mt2701-dsi"; in the devicetree, and to drop this patch - but that's not possible, check below. The problem that Krzysztof was raising is that the bindings currently define the "mediatek,mt8167-dsi" as single compatible with no fallback, and removing it would break the ABI (as the bindings are not used only for Linux, but also for bootloaders). Even though I can try my best to convince him, this is a real problem: mistakes were made in the past, and the only way to get the mt8167-dsi supported right now is to, unfortunately, add the compatible in mtk_dsi.c. I don't like that, and I see that you (CK) don't as well, but that's the result of past mistakes... and apparently we can't do anything about this if not to *uselessly clutter the driver* with that. So, that said... I'm sad to say that this patch is the only way to get this SoC probed by mtk_dsi and that there's no other way around it, because the bindings maintainers are forbidding us from removing the bad compatible (which was *never* used anyway) from there and making it right with allowing it only under 2701 fallback. I'm moving krzk to the To: field of this email in hope to get back a reply that sounds like "you misunderstood me, you can do it", but I'm not positive about this. Krzysztof, please confirm or deny what I said. Regards, Angelo > Regards, > CK > >> >> Thanks! >> >> [1] https://urldefense.com/v3/__https://patchwork.kernel.org/project/linux-mediatek/patch/ff920a7cc94f2b0c03d4bb55142030fded30d07c.1771258407.git.l.scorcia@gmail.com/__;!!CTRNKA9wMg0ARbw!lIBnCRkybM1oxoARb70JlLMPlXHKqW9dwSmVqXGsvj3LE9hsWuINkPgtrlr8Jl8-atOvzYoMjtavHOr3$ >> >>>> >>>> Signed-off-by: Luca Leonardo Scorcia >>>> --- >>>> drivers/gpu/drm/mediatek/mtk_dsi.c | 1 + >>>> 1 file changed, 1 insertion(+) >>>> >>>> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c >>>> index af4871de9e4c..ad10e86b161d 100644 >>>> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c >>>> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c >>>> @@ -1301,6 +1301,7 @@ static const struct mtk_dsi_driver_data mt8188_dsi_driver_data = { >>>> >>>> static const struct of_device_id mtk_dsi_of_match[] = { >>>> { .compatible = "mediatek,mt2701-dsi", .data = &mt2701_dsi_driver_data }, >>>> + { .compatible = "mediatek,mt8167-dsi", .data = &mt2701_dsi_driver_data }, >>>> { .compatible = "mediatek,mt8173-dsi", .data = &mt8173_dsi_driver_data }, >>>> { .compatible = "mediatek,mt8183-dsi", .data = &mt8183_dsi_driver_data }, >>>> { .compatible = "mediatek,mt8186-dsi", .data = &mt8186_dsi_driver_data }, >>>> -- >>>> 2.43.0 >>>> >>>> >> -- >> Luca Leonardo Scorcia >> l.scorcia@gmail.com >