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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2286FC433F5 for ; Fri, 28 Jan 2022 11:09:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348075AbiA1LJe (ORCPT ); Fri, 28 Jan 2022 06:09:34 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:24414 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238642AbiA1LJJ (ORCPT ); Fri, 28 Jan 2022 06:09:09 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1643368149; 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=35G0EZH/o9dD2crtrnjLKHLlwbAMq77uRxgBW+YN2gA=; b=BQEkv8S6mM3zkeWHZMmBR2u9CELc+3S+p6HDdiO248GOLo53LPGbJkdwSvb6Cc3a7o96fd yrm7J5FsS3OD1/3ZDIkMiq853lhIemsQlh55gz80qilpv74m284v/CRAL1O9XZ7E9OsPNy 4dcFkEJ3pJDGp/3OmGu3cuVdVeczzrs= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-642-FP1g3hS1PgadjIn5JFmPxQ-1; Fri, 28 Jan 2022 06:09:07 -0500 X-MC-Unique: FP1g3hS1PgadjIn5JFmPxQ-1 Received: by mail-wm1-f71.google.com with SMTP id f7-20020a1cc907000000b0034b63f314ccso2805389wmb.6 for ; Fri, 28 Jan 2022 03:09:07 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=35G0EZH/o9dD2crtrnjLKHLlwbAMq77uRxgBW+YN2gA=; b=v5N7JM/cRDk4AMXIc/l//MiQ8xTlyRPB3UwWZ2kzCNuUCI3vNs3X31P9BkBT60CNkA vuYLwYzdTMkVm6zQp6JsNXm6uEzOv3iXgQbcAVXSG5kZd2dEszl9kIpXG54U1IFM4RT9 tdnldREa0H9RoBwNedpuT/4SmXN+ESJYtEiYaVqh8msqhi14BbbQ/gGJkj6MKRXSIUYJ jnoPeX08T+/PjNXq+zzk+Jjvt9eg5PqIOxqe0rfVYTslO4eCXVhpABIH3BnxgfpZeZCk fwFdz1/XFZV/i4vS8UoN1ghFPV8uQMqngZHAZVSeRDu7AzSE7FQq1zksG2whMvJWyepP gY3w== X-Gm-Message-State: AOAM531sRgYb0UTLlJwp10kkXwpxQv53OPw/dkVrpMfohWBAjMxl3fmn 3VHd1P2lgCiF+eA9Ya6kcEdWWljFABDESmxRAE1yK/vxnbG7h4xiFJOR/vRnVZJYUGOqXGpeoWR MM3mxchTdRC0QGvAw7nPPwTiu X-Received: by 2002:a05:600c:2948:: with SMTP id n8mr7006475wmd.61.1643368146525; Fri, 28 Jan 2022 03:09:06 -0800 (PST) X-Google-Smtp-Source: ABdhPJyK3G/FxIBrsORiLFoh6WUx871HJXkDD26z2CbztjoHQ9dhXPymdoC9rR9lW4k1VOIwEQjifw== X-Received: by 2002:a05:600c:2948:: with SMTP id n8mr7006453wmd.61.1643368146276; Fri, 28 Jan 2022 03:09:06 -0800 (PST) Received: from [192.168.1.102] ([92.176.231.205]) by smtp.gmail.com with ESMTPSA id m25sm1594570wml.47.2022.01.28.03.09.05 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 28 Jan 2022 03:09:05 -0800 (PST) Message-ID: <9ae2c7ba-133e-7c6f-190b-97158f241c7f@redhat.com> Date: Fri, 28 Jan 2022 12:09:05 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH v2 31/37] drm: rcar-du: Add support for the nomodeset kernel parameter Content-Language: en-US To: Thomas Zimmermann , Laurent Pinchart Cc: Kieran Bingham , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20211217003752.3946210-1-javierm@redhat.com> <20211217003752.3946210-32-javierm@redhat.com> <164336121612.533872.1685181669511488706@Monstersaurus> <584f1343-b285-bf8e-e48c-764c2a56bce3@suse.de> From: Javier Martinez Canillas In-Reply-To: <584f1343-b285-bf8e-e48c-764c2a56bce3@suse.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/28/22 11:46, Thomas Zimmermann wrote: > Am 28.01.22 um 11:34 schrieb Laurent Pinchart: [snip] >>> >>> It cannot be 'mode-setted'. We get a pre-configured framebuffer from the >>> firmware or bootloader. Whatever we draw there shows up on the screen. >> >> I doubt that's going to work as you expect, clocks and regulators will >> get disabled at boot if not used by any driver. > > Simpledrm and simplefb attach to these firmware framebuffers. Both > drivers look at the device tree nodes to acquire the relevant clocks and > regulators. > Laurent is correct that in some cases it might be an issue. For example, if a SystemReady ES image is booted using the U-boot EFI stub instead of bootz. In this case the system will be presented as EFI and the firmware framebuffer just taken from the EFI GOP. There won't be any Device Tree node describing the clocks, regulators, etc that are required for the framebuffer to work. The user then will have to pass clk_ignore_unused, pd_ignore_unused and maybe other cmdline params (or even hack a DT to set regulator-always-on for needed regulators). But that is also true if the user wants to disable the real DRM driver with modprobe.blacklist=rcar-du-drm. What this patch does is just to make all DRM drivers consistent and honour the nomodeset param (whose name is really misleading but we can't change that). Best regards, -- Javier Martinez Canillas Linux Engineering Red Hat 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 920DBC433EF for ; Fri, 28 Jan 2022 11:09:12 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A6C8210EF1D; Fri, 28 Jan 2022 11:09:11 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id 63B2010EEFC for ; Fri, 28 Jan 2022 11:09:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1643368149; 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=35G0EZH/o9dD2crtrnjLKHLlwbAMq77uRxgBW+YN2gA=; b=BQEkv8S6mM3zkeWHZMmBR2u9CELc+3S+p6HDdiO248GOLo53LPGbJkdwSvb6Cc3a7o96fd yrm7J5FsS3OD1/3ZDIkMiq853lhIemsQlh55gz80qilpv74m284v/CRAL1O9XZ7E9OsPNy 4dcFkEJ3pJDGp/3OmGu3cuVdVeczzrs= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-502-TqDghe7QPt6y0z2MuvtxNg-1; Fri, 28 Jan 2022 06:09:07 -0500 X-MC-Unique: TqDghe7QPt6y0z2MuvtxNg-1 Received: by mail-wm1-f70.google.com with SMTP id q125-20020a1c4383000000b003503e10c027so1348287wma.2 for ; Fri, 28 Jan 2022 03:09:07 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=35G0EZH/o9dD2crtrnjLKHLlwbAMq77uRxgBW+YN2gA=; b=KhCvE7T56MKG9aTy+otME7IU2v/TGFsYPPV4k5iqLKrLk3h3Izi01LA0VwKPgtPhaB acBMh+EJDZTKzls0+Irdj/KLwUaUXq0ZFzOmRkjEzT0L2W6i989q7vNVXdnGzMLOUqVV P7X8mWA0stXhl2G2PnaKW6t7rrsKRzsvmK3Tdwz6Om2CRHzVMBEtFKvxSkEcJM/VRQ/d piYARJIQWgvGXPzSu7qRzWUDIsipV4RjIx92nX47wtrDQWCaI0ztmk+hCCWe43wl2iHt wxvmV7IT5r5vgCw4D9JpBsC6KskuXBnTAvEiC9izbMC8CX3S1TIALDeIT5yx/XbMclM2 EcKw== X-Gm-Message-State: AOAM533scXP6DyHSfDKSIAhw7/emDgMKSoiEDyBBwTytxItUTggfqgRP nz2hNKF5ceEbT2SBbkwOQ9fVRuELKLXfpYYhDKLgbxEVOQygwEu3yjBi+hD03iLcwTDyFT8Vg2m Bo8OzkOdsYeXxum3BK9Ny24U/fMv9 X-Received: by 2002:a05:600c:2948:: with SMTP id n8mr7006477wmd.61.1643368146526; Fri, 28 Jan 2022 03:09:06 -0800 (PST) X-Google-Smtp-Source: ABdhPJyK3G/FxIBrsORiLFoh6WUx871HJXkDD26z2CbztjoHQ9dhXPymdoC9rR9lW4k1VOIwEQjifw== X-Received: by 2002:a05:600c:2948:: with SMTP id n8mr7006453wmd.61.1643368146276; Fri, 28 Jan 2022 03:09:06 -0800 (PST) Received: from [192.168.1.102] ([92.176.231.205]) by smtp.gmail.com with ESMTPSA id m25sm1594570wml.47.2022.01.28.03.09.05 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 28 Jan 2022 03:09:05 -0800 (PST) Message-ID: <9ae2c7ba-133e-7c6f-190b-97158f241c7f@redhat.com> Date: Fri, 28 Jan 2022 12:09:05 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH v2 31/37] drm: rcar-du: Add support for the nomodeset kernel parameter To: Thomas Zimmermann , Laurent Pinchart References: <20211217003752.3946210-1-javierm@redhat.com> <20211217003752.3946210-32-javierm@redhat.com> <164336121612.533872.1685181669511488706@Monstersaurus> <584f1343-b285-bf8e-e48c-764c2a56bce3@suse.de> From: Javier Martinez Canillas In-Reply-To: <584f1343-b285-bf8e-e48c-764c2a56bce3@suse.de> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=javierm@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kieran Bingham , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 1/28/22 11:46, Thomas Zimmermann wrote: > Am 28.01.22 um 11:34 schrieb Laurent Pinchart: [snip] >>> >>> It cannot be 'mode-setted'. We get a pre-configured framebuffer from the >>> firmware or bootloader. Whatever we draw there shows up on the screen. >> >> I doubt that's going to work as you expect, clocks and regulators will >> get disabled at boot if not used by any driver. > > Simpledrm and simplefb attach to these firmware framebuffers. Both > drivers look at the device tree nodes to acquire the relevant clocks and > regulators. > Laurent is correct that in some cases it might be an issue. For example, if a SystemReady ES image is booted using the U-boot EFI stub instead of bootz. In this case the system will be presented as EFI and the firmware framebuffer just taken from the EFI GOP. There won't be any Device Tree node describing the clocks, regulators, etc that are required for the framebuffer to work. The user then will have to pass clk_ignore_unused, pd_ignore_unused and maybe other cmdline params (or even hack a DT to set regulator-always-on for needed regulators). But that is also true if the user wants to disable the real DRM driver with modprobe.blacklist=rcar-du-drm. What this patch does is just to make all DRM drivers consistent and honour the nomodeset param (whose name is really misleading but we can't change that). Best regards, -- Javier Martinez Canillas Linux Engineering Red Hat