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 5CE6FCCF9E3 for ; Sun, 2 Nov 2025 17:15:41 +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:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=pVIWxvbG6hS59cIjcOfk1tNz+O1dirw/jStQigJNNw8=; b=TyJkomHGKQ/zQrcgQdRDsKozKw X1kRmfm/yjMsvd9vK9OB8XJJ6wYSx/sLd7p8eK8vKwtILNLgZdKnHIIaleIQK0DlnhPsdviQNsho5 dc4WravMqhCMF+KANk14okIYNhgYi0zOWLg3vx/+NIh1m1/NEk3CqYoxp5XCKMk6zLbiA2da7QEKI niF7N75kxgrA7ELYElUcWWVgK3rg9Uwn5mjdW+Z8ETR0v28jiOoupJmN0jywD4UjaDMsX0+xasekm 1HCl0oL5WxilfeYs2G9wQUuuMEDEmvXo7RAqH4wnS8KGMxNOurSKlCq5WmlZ8iQ4JITnfz7TawgOh OqCi8M1A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vFbfz-00000008gQM-2UDe; Sun, 02 Nov 2025 17:15:35 +0000 Received: from mout-p-101.mailbox.org ([80.241.56.151]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vFbfw-00000008gOs-3rKK for linux-arm-kernel@lists.infradead.org; Sun, 02 Nov 2025 17:15:34 +0000 Received: from smtp202.mailbox.org (smtp202.mailbox.org [IPv6:2001:67c:2050:b231:465::202]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-101.mailbox.org (Postfix) with ESMTPS id 4d01Z91lrSz9tKX; Sun, 2 Nov 2025 18:15:29 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mailbox.org; s=mail20150812; t=1762103729; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=pVIWxvbG6hS59cIjcOfk1tNz+O1dirw/jStQigJNNw8=; b=kiczCTwovFK3kcxFGIgvfX7t7jHPp/LysnFqW8CukOZyAt9lddGQ3LZjsRc5kBbNyeJQkE 35C0ueF8JCz0yG3IyQpmCn0bFCzpCDOKrClYy+nRQlL/NOMItmREuCjsRRHaNFJJSm6UBW yyRGaOsuByxhyHLPHbPURhYEbLg9Y/Vtpx7ea27bu1uJ43EUn62mWBPFiTjIMSqzhTsXz9 /PjwErrRPgda7/G2Dx93s5x9DRwJZkIM1aMbr6fn1xPpcKkZv7kE4/HcZGG/U/7BcCT/dB eQPnaZ5pkUV7XVbP4EL2CidnZ4JR0FZht6OIObCeXliM0b1y9wG0gZFoosE5ZA== Message-ID: <30dc382c-6b26-4b2a-81ab-67ac5bbf7150@mailbox.org> Date: Sun, 2 Nov 2025 17:41:38 +0100 MIME-Version: 1.0 Subject: Re: [PATCH 01/39] dt-bindings: display: imx: Document i.MX95 Display Controller DomainBlend To: Ying Liu , Rob Herring Cc: "dri-devel@lists.freedesktop.org" , Abel Vesa , Conor Dooley , Fabio Estevam , Krzysztof Kozlowski , Laurent Pinchart , Lucas Stach , Peng Fan , Pengutronix Kernel Team , Shawn Guo , Thomas Zimmermann , "devicetree@vger.kernel.org" , "imx@lists.linux.dev" , "linux-arm-kernel@lists.infradead.org" , "linux-clk@vger.kernel.org" References: <20251011170213.128907-1-marek.vasut@mailbox.org> <20251011170213.128907-2-marek.vasut@mailbox.org> <20251015132442.GA3241958-robh@kernel.org> <5c5bb009-3463-4282-946f-3ae93fab11ec@nxp.com> Content-Language: en-US From: Marek Vasut In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-MBO-RS-META: b47hecses99gtkdixbqohop36pxjecdy X-MBO-RS-ID: df5e035099bd363f9aa X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251102_091533_123125_0C3746AB X-CRM114-Status: GOOD ( 18.07 ) 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 10/18/25 8:09 AM, Ying Liu wrote: Hello Liu, >>> BTW, I confirm that two Domain Blend Units exist in i.MX95 DC while they >> don't >>> exist in i.MX8qxp/qm DCs. And, as you can see, this unit supports multiple >>> modes, this would impact how an OS implements a display driver a lot, >> especially >>> Blend mode and SidebySide mode. >> >> There is one thing which specifically concerns me about the DB, it seems >> to be capable of blending two inputs from different security domains, is >> that correct ? > > For now, I know nothing more than the DT binding description here, i.e., > two inputs are combined to one output in four modes. And, DB cannot be > bypassed IIUC. I see. >>> As patch 39 shows, there are 3 interrupts - domainblend{0,1}_shdload, >>> domainblend{0,1}_framecomplete and domainblend{0,1}_seqcomplete. >> It seems we currently do not use either clock or interrupts on either >> domainblend or layerblend IPs, but maybe DB and LB are different and LB >> really has no clock/interrupts ? > > If you take a look at NXP downstream kernel, it uses > domainblend{0,1}_shdload IRQs in CRTC driver and I believe that upstream > driver should use them too. Can you please tell me what exactly is this IRQ signalling ? > DB and LB are different. DB is in Display Engine, while LB is in Pixel Engine. > This pipeline sort of tells how LD and DB are connected: LB -> ED -> DB. > > LB has no interrupts. And since it processes pixels in Pixel Engine with AXI > CLK and it can be configured via the AHB interface of DC with CFG CLK, I'd > say it kind of inherits AXI CLK and CFG CLK from Pixel Engine and DC > respectively. See the diagram in fsl,imx8qxp-dc.yaml, you'll find those > clocks. Thank you for the clarification. And sorry for my late reply. -- Best regards, Marek Vasut