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 0D9F8C433FE for ; Wed, 12 Oct 2022 13:13:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229585AbiJLNNN (ORCPT ); Wed, 12 Oct 2022 09:13:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53600 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229815AbiJLNNA (ORCPT ); Wed, 12 Oct 2022 09:13:00 -0400 Received: from out3-smtp.messagingengine.com (out3-smtp.messagingengine.com [66.111.4.27]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D6327FE6F for ; Wed, 12 Oct 2022 06:12:59 -0700 (PDT) Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by mailout.nyi.internal (Postfix) with ESMTP id C0B415C008B; Wed, 12 Oct 2022 09:12:56 -0400 (EDT) Received: from imap51 ([10.202.2.101]) by compute3.internal (MEProxy); Wed, 12 Oct 2022 09:12:56 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arndb.de; h=cc :cc:content-type:date:date:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:sender:subject :subject:to:to; s=fm2; t=1665580376; x=1665666776; bh=Ct4fEaGcnx W60ym69bXCH9mc9qXYaXsYB/Q4TrRfNec=; b=gDDtqy2G6/6ho8fsUc2YXwQBNy qDV9YtM36YfT/3GCfD5l/gpVQMsIkKRm1+8hVv7KWOBvguYwxYgrdc82rQYoR6j+ Sprdv8wKqTKDxZ+5QCgLDsAm3SgRkU/g3bDfxfFgplzoGKQtPj4Nwz50AGvbxeOO hxrCnwMfk6eKrCenRifiNywRyiz1LYLBSA2OdFNbXS0BVSuoWBpaTfzyptQKHxLI urHMKY0Rq9CZlOESkHl6iI6Cx3w6SbXp14Ht89wEoj4JUWycoyHXwglQdvOx+0qc puBAbrYvDqm8+Xr4AWmLbdyfG5YIQDDCQIx/vzbWQy3f/LXNDnG1RSIFdh+Q== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:date:date:feedback-id :feedback-id:from:from:in-reply-to:in-reply-to:message-id :mime-version:references:reply-to:sender:subject:subject:to:to :x-me-proxy:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm3; t=1665580376; x=1665666776; bh=Ct4fEaGcnxW60ym69bXCH9mc9qXY aXsYB/Q4TrRfNec=; b=OWCSrc95pvOMPngNghm6dRIUz7Fu8nhJoQ+BtGUnfmsK qLWORC8NXA5dMYP+euL376k3W2dX+gaOgp3NyJQN82POobBdn/jzpj+tpFMYSrS6 cJcdRr3ERrJ06jXmLznEb0wiSXRvRdAOZ6mEEupKYqQCnTt+tLU5fqEfqdZGmGVV Z1o9Yqa7IJFDDLUXSvXpCIUbmCxrXugJS3K47ayuFjOk+7ev1TdQ3YYZHpWIUJuH vzb33UGIMNSSaYckRf426yL3PsCItJRTOSYszLwLwZK8hZ4BE4z0bRgejy3pf36d TAdEB9+WhwNOGRa9JZg6AxRLFRPjms5J1n+ZaXKPMQ== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvfedrfeejkedgiedvucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepofgfggfkjghffffhvfevufgtsehttdertderredtnecuhfhrohhmpedftehr nhguuceuvghrghhmrghnnhdfuceorghrnhgusegrrhhnuggsrdguvgeqnecuggftrfgrth htvghrnhepffehueegteeihfegtefhjefgtdeugfegjeelheejueethfefgeeghfektdek teffnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomheprg hrnhgusegrrhhnuggsrdguvg X-ME-Proxy: Feedback-ID: i56a14606:Fastmail Received: by mailuser.nyi.internal (Postfix, from userid 501) id 9653DB60086; Wed, 12 Oct 2022 09:12:55 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface User-Agent: Cyrus-JMAP/3.7.0-alpha0-1047-g9e4af4ada4-fm-20221005.001-g9e4af4ad Mime-Version: 1.0 Message-Id: <76d8a408-fc3e-4bd1-91c5-8278f7469979@app.fastmail.com> In-Reply-To: <0a15ecf5-939d-3b00-bcde-0fc7b449cfda@suse.de> References: <20220928105010.18880-1-tzimmermann@suse.de> <20220928105010.18880-6-tzimmermann@suse.de> <23333ff7-3ae1-494f-7abe-62da6698fd00@redhat.com> <83071743-a7f2-f761-baa3-da688f26b5e3@suse.de> <9162f41f-28c3-493c-ab54-b1c4a2fdf494@app.fastmail.com> <654e3cfe-80d7-46c9-8e5e-461846e4df35@app.fastmail.com> <866c7033-0d4e-7b5d-008c-8eb16f99498b@suse.de> <0a15ecf5-939d-3b00-bcde-0fc7b449cfda@suse.de> Date: Wed, 12 Oct 2022 15:12:35 +0200 From: "Arnd Bergmann" To: "Thomas Zimmermann" , "Javier Martinez Canillas" , "David Airlie" , "Daniel Vetter" , "Helge Deller" , "Maxime Ripard" , sam@ravnborg.org, "Michal Suchanek" , "Michael Ellerman" , benh@kernel.crashing.org, "Paul Mackerras" , "Geert Uytterhoeven" , mark.cave-ayland@ilande.co.uk Cc: linux-fbdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH v4 5/5] drm/ofdrm: Support big-endian scanout buffers Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org On Wed, Oct 12, 2022, at 2:00 PM, Thomas Zimmermann wrote: > > Could well be. But ofdrm intents to replace offb and this test has > worked well in offb for almost 15 yrs. If there are bug reports, I'm > happy to take patches, but until then I see no reason to change it. I wouldn't change the code in offb unless a user reports a bug, but I don't see a point in adding the same mistake to ofdrm if we know it can't work on real hardware. I tried to find out where this is configured in qemu, but it seems to depend on the framebuffer backend there: most are always little-endian, ati/bochs/vga-pci/virtio-vga are configurable from the guest through some register setting, but vga.c picks a default from the 'TARGET_WORDS_BIGENDIAN' macro, which I think is set differently between qemu-system-ppc64le and qemu-system-ppc64. If you are using the framebuffer code from vga.c, I would guess that that you can run a big-endian kernel with qemu-system-ppc64, or a little-endian kernel with qemu-system-ppc64le and get the correct colors, while running a little-endian kernel with qemu-system-ppc64 and vga.c, or using a different framebuffer emulation on a big-endian kernel would give you the wrong colors. Which combinations did you actually test? Arnd