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 2B4D5FB5179 for ; Tue, 7 Apr 2026 06:33:13 +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:MIME-Version: Content-Transfer-Encoding:Content-Type:In-Reply-To:From:References:Cc:To: Subject: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=+1RIFue3tOxRIWmbA0AlCG8okArVMZO8hH22Nj/muv8=; b=3LnSCov3YCvO+/Dm9gzPpc30tW BQ7Zfo8NhQFuIeMI3iMA3dXOXhSlZBpSXeodxITjclTI7nx98JjV3SUr31BNPxIfidG8XeTbH2LjK lCcy21Oa1IyPGeVuzRAa/CtCOGh362iHpYJgROaXFn14iHxh9fynG09TobyZBwGBAezBNmdQAFN2/ Wvz9f6+I1bwW3tFIcERFg0jmj5MClQX3FwpWRn85goEhQ3ZySu1SUwqJHN+UYEJJMzmfgTIen6Eyq mq4ix9ih2g9R/k1mK79QsDGRomX6NsbVffNCD4l6S30s6mwhuKpxzzQjBxDWJMoIOStuDXSqoHfxb r1rBCcZQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w9zzp-00000005zqk-2FkJ; Tue, 07 Apr 2026 06:33:09 +0000 Received: from mail-norwayeastazlp170130007.outbound.protection.outlook.com ([2a01:111:f403:c20f::7] helo=OSPPR02CU001.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1w9zzn-00000005zqO-08Rn for linux-arm-kernel@lists.infradead.org; Tue, 07 Apr 2026 06:33:08 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=njxzMskurJJnFs2oqxzExm52tsGeYzcNenE2w7uAhuX7tdSpijfw/OVBNTimnjKc6bRSuW3Gu/ZYBJJQOrD8WpeBLzbvEZvsQ264wawt3k1H0hdvsGKT/ePTxJQaCTZElGDtd1JXuoggxUl9c28IY4F5Tu66oq4Id1l+PTMSreWLlCU6WAvlg6e5O0UkqRV6kOFwQCk93QFbEPrs9uP+IfjgIyHO/m7xWjDjIb7+ROlX0TM1Cr+vO2vK7XlOi+fYacD8dAsEOwPc1R7UvRVKh7k4l6kamO/XS0nsQ+h6+OXeMA046qHXUx2qOZjYX0b09INstT5YihxA3LqnBytBpw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=+1RIFue3tOxRIWmbA0AlCG8okArVMZO8hH22Nj/muv8=; b=WsXL3V2Zi2eH9h5302Vh8RgfBehzcJCZMwtcMv63ofvghcJbLI/W6er7GN2KhOZlhla37U5wX5I/4h8H3kxjcAB5sT3/tlDrEaZO+T36qXPhq64u5MlTBkkMMTSZEDMSDP5j3OMcH2O7Jdi5XoNcvqjZ4pH7ADPcj7GxsB5pN30ZAI4NhJrh9JYtFD0CweySW+8ApZALUuBijl+lgOPoH4iDwxgnyau2jdpx8LMw+srus8nQWCbx9t8uAF7uwOx+T9dNpGjI+9Xbpj6c+yWOtgKayhA+amiu+Y/uRTaMSxVghLrf93IkxWxW05SzgB3zgCqT5JgH6HBAT50gxpyocg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nxp.com; dmarc=pass action=none header.from=nxp.com; dkim=pass header.d=nxp.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nxp.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=+1RIFue3tOxRIWmbA0AlCG8okArVMZO8hH22Nj/muv8=; b=egSJlnCHSC+UnxPjBK2QOOYcKt1Ojfbn2FslSpbI6ArlpV87pI8giTohfJKelTKyNCvPcxuCHzlCIUG3fcXA+PCqVjpLJO05sQDHPkeytsx/poIpuoNjcOqqIjweUIqQsXfLgV6fb62TO4137xy8SiazMo7rus3Ta60tpICXUU9rcvMxT04xl9B+P3yVAOnVYITLvd+JCZAth1R9QgTV4CW5fR1Xm5n7A2JcDGtOWH+asptL7YToHiy3qQ+JeOv3Y5BGvUPV6/KwbcQ1M3/vnllbfrJ4m6sF6at+qoh8khtPYPFdlDmeB49NRp7iNEGtlt85F5fzu2pVJ4AkLQV8ag== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nxp.com; Received: from AM7PR04MB7046.eurprd04.prod.outlook.com (2603:10a6:20b:113::22) by AS1PR04MB9682.eurprd04.prod.outlook.com (2603:10a6:20b:472::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9769.20; Tue, 7 Apr 2026 06:33:00 +0000 Received: from AM7PR04MB7046.eurprd04.prod.outlook.com ([fe80::4609:64af:8a4b:fd64]) by AM7PR04MB7046.eurprd04.prod.outlook.com ([fe80::4609:64af:8a4b:fd64%3]) with mapi id 15.20.9769.016; Tue, 7 Apr 2026 06:33:00 +0000 Message-ID: Date: Tue, 7 Apr 2026 14:34:16 +0800 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/2] drm: lcdif: Wait for vblank before disabling DMA To: Paul Kocialkowski , dri-devel@lists.freedesktop.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Marek Vasut , Stefan Agner , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Frank Li , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , Lucas Stach , =?UTF-8?Q?Krzysztof_Ha=C5=82asa?= , Marco Felsch References: <20260402183351.3281123-1-paulk@sys-base.io> <20260402183351.3281123-3-paulk@sys-base.io> From: Liu Ying Content-Language: en-US In-Reply-To: <20260402183351.3281123-3-paulk@sys-base.io> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MA5P287CA0149.INDP287.PROD.OUTLOOK.COM (2603:1096:a01:1d7::19) To AM7PR04MB7046.eurprd04.prod.outlook.com (2603:10a6:20b:113::22) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: AM7PR04MB7046:EE_|AS1PR04MB9682:EE_ X-MS-Office365-Filtering-Correlation-Id: f160ce8c-10ca-460e-cd4b-08de946f837c X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|366016|376014|1800799024|19092799006|18002099003|22082099003|56012099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:AM7PR04MB7046.eurprd04.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(366016)(376014)(1800799024)(19092799006)(18002099003)(22082099003)(56012099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?RG1TV1Nnc0RjRVBWS2VJU1Q5Qy9YTTF1ejhSNXlOSEwxeWw1d21sL1VISzgx?= =?utf-8?B?Tmd2cjR6SEpFdDhrMklyWE9jMGJvS1l5c25mS2xPcENOajhEY00zSWtGL0FP?= =?utf-8?B?VnJLY0wwZ3dUY0xMNUNtdXhXSnZYRUExY0thS09Edzd0Y0JhN0NvVXp6cDBn?= =?utf-8?B?ZmZkaWM3SncyNm1uZFJxT2p2b0toMXJ0TndnU0ljUElyTHNGQkovdWFMWE9K?= =?utf-8?B?d2k3eW1lSVZhSzNkM3l6MzhnenlYS2NINVcrRlplSUcvSVRZWW5qZTg5UWho?= =?utf-8?B?TU52Z0lycm1zRHRPeUdNa3ptM3pPQ00yZU83VmlZRmkrNysvU2tmd08zdWts?= =?utf-8?B?UzVya2hOQU1HNFJaTlNoS2NnM0RpOEIyNWVVQms2ZnVSYWljcHhMYXdwN2Rp?= =?utf-8?B?Vkg0SitDMTQzQ05kQmRmcDUweFdEblpZdERkVm04NU9WZ2ZwMlNhZEU2cWVH?= =?utf-8?B?MUc2a2w1elU5RzMxbWQwMkhhbTR4MzBvRHlidHRnUUpNSWVRampvT0pyRjJm?= =?utf-8?B?K1hka1QrTzZCY0pqSnhQaUtabGppZEI4U2Y2TmM5c2dPSmQzaWFlZVRCdjZp?= =?utf-8?B?YmZWcEoyZW1FRmoxUUtjZHZKbGFWUW1EME9udzkzNXVWUE5vWVcraC9MRTFD?= =?utf-8?B?aTRUbWlPOWNIOVZmeTI0d09CL1lmNWlHNmNnY1Ria0c5ZEtPVklBcnRKTVZU?= =?utf-8?B?UGNVODkxMURxVE50TE1ESml0RDdoOUtkU3Y4UWJVZnZmUEx2T0FQcGZnWVY5?= =?utf-8?B?bFlaalVlcURXVzJrTXNIZGJGU0UzdzZLK2hZeW5kaE43UXNYNnZ3YjNZRVFp?= =?utf-8?B?VC9lNDBBOU1TUkZ1bVFVZGtoSXJMakVTU2E3aFhROElpVlBFL3UzS0k4ZDBw?= =?utf-8?B?VGlXV0Rsays3dlNlbndmNTFWZ2g4dDhFUHo2M1lHcEIzN1gwYVdkN2lZWHF4?= =?utf-8?B?aWNsc3ovZHJMZlpmcDVReWp6UW03MzcvNzdzVnlBYTdIdTdJZjQ2Z2pkV3pF?= =?utf-8?B?aDRUdHNvQjUyMlZuNkdSRm03UVA3bXlad0xlVkdZMVVpa3diYXJXMStQV0dq?= =?utf-8?B?QzIyMG9JTGx4WTBjZkJRZFRwNFlVdGttNG5NSnZMeHJvY2o0bFpLNGZPVnAv?= =?utf-8?B?TG5jeVM2YVFjVkVrc2VEYk9Rb0h2TFlyMm1aMUswci96Mm1nTUFUeTdTTGxz?= =?utf-8?B?dmxteEI4T0IwRytXOFNaV21JTTFhVXNNRFZlcnF1RFNrYTZ6eldxL2tmN3pk?= =?utf-8?B?UkRFRWlFMUlCUjZXTktLRTFQaEt2VlA0WFBtUXRYckVRaTNJL3RmaFJRU28w?= =?utf-8?B?cXB3bkJVY1Ayd3gxZm50N1JCa2dnTUZPL3dmMTlPSXBZekFzSEdDa3E1YVVZ?= =?utf-8?B?MEVYQUJ4NGwrZHl3VW9NZkpJRElmdloyeHBRL3NsTkZVWHBqeHR6TG4zRjZt?= =?utf-8?B?WlNSUFhMZklKMWhMMHFhc1F0MTRnRUtweHQ3QkRTY3dRZUFmYWVkRUl3OENX?= =?utf-8?B?WmlpUGVhc29FN3JHU1hGalpRbnFzdWVaTkJHV0g0NUlIVEFFQi9wYkVzdEIw?= =?utf-8?B?SFp6T2p1Rm0rRWoxcXp4Q2pLVHdjL3UrYlNsdEZva3RTTmIwWjZma0tWQkE2?= =?utf-8?B?NFN6UUlUV0hTWVVOdUl2QmtEdEM2dkhHZmxPNlkvR3BGUGVKekNZQkY5LzdH?= =?utf-8?B?aWQ0SFdoNnFnKzg1VW5Fd1hSc05WR2JqTWhQV09iVHNDUmJkVENpQkhwYTJJ?= =?utf-8?B?TlMzbU9rZUExVjhGbmZyTmZLUEptTHVIcHV1dzVWRys5VnpDNW90LzkrV0I4?= =?utf-8?B?RWplQ2h4b3FHemlvOWl6RkEreExhSkFkWHFyR29hakxUK1l1RVc3R0JSbHRP?= =?utf-8?B?UjAvQjYvaFdUaVJKSUE4MjJ5U09KeDdwdWUxa0ZUcVNucXVyZm1CKzZZUUVs?= =?utf-8?B?VXFZT0IxajJsVldnUlFQVFk3TnhjK1ViZTRUanZoUzU2N2hlMmdMNEMzR0F3?= =?utf-8?B?aldtNE5BQUpRTVdRODVmTWdPMDZUL0tBQ0d4S3NRamxVeXRUQ2h4TU5CR2I1?= =?utf-8?B?QWEvNTF2akxzdHA0amN0d1U2UzhLSlVnbEZFZHRnU2hRYjhxTmNQNUgrQk1N?= =?utf-8?B?aTY0YnVFOFZ0WTBxUGczcWh0VDlLbjFnK0ZBWGpjb3h6bURjN2c1K2tQZ3NL?= =?utf-8?B?RHpETkZ5UFVoYnpPQ1ZRZGY0WXFyNVdEL1FpRFBGaDVyY216dkdKcXQ3V3Rn?= =?utf-8?B?MVdNQTJtM2pJLzZYZFI0MmFJWTJVOG1lanZBN0RwTmE1MmxHNEs3R1Joamhy?= =?utf-8?B?aG9iVW5MbzRsa2dqZTR2OE1IbHpSblNrSTRPQTlnUnk2RndtdHgrUT09?= X-OriginatorOrg: nxp.com X-MS-Exchange-CrossTenant-Network-Message-Id: f160ce8c-10ca-460e-cd4b-08de946f837c X-MS-Exchange-CrossTenant-AuthSource: AM7PR04MB7046.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 07 Apr 2026 06:33:00.3603 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: C5SIIR5yE/aaqcR9WD8hPzpgDWlGhqVXVjZXqtD5SNUV90vsa20yw5o3DXSFsTf9rybXCOe9iC+ubUeMQYfx1w== X-MS-Exchange-Transport-CrossTenantHeadersStamped: AS1PR04MB9682 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260406_233307_241367_2FFA6385 X-CRM114-Status: GOOD ( 14.53 ) 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 Hi Paul, On Thu, Apr 02, 2026 at 08:33:51PM +0200, Paul Kocialkowski wrote: > It is necessary to wait for the full frame to finish streaming > through the DMA engine before we can safely disable it by removing > the DISP_PARA_DISP_ON bit. Disabling it in-flight can leave the > hardware confused and unable to resume streaming for the next frame. > > This causes the FIFO underrun and empty status bits to be set and > a single solid color to be shown on the display, coming from one of > the pixels of the previous frame. The issue occurs sporadically when > a new mode is set, which triggers the crtc disable and enable paths. > > Setting the shadow load bit and waiting for it to be cleared by the > DMA engine allows waiting for completion. > > The NXP BSP driver addresses this issue with a hardcoded 25 ms sleep. > > Fixes: 9db35bb349a0 ("drm: lcdif: Add support for i.MX8MP LCDIF variant") > Signed-off-by: Paul Kocialkowski > Co-developed-by: Lucas Stach There is a warning reported by checkpatch.pl: WARNING: Co-developed-by: must be immediately followed by Signed-off-by: #23: Co-developed-by: Lucas Stach With this fixed: Acked-by: Liu Ying Thanks! -- Regards, Liu Ying