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 C9B38C43334 for ; Tue, 12 Jul 2022 08:32:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232654AbiGLIcj (ORCPT ); Tue, 12 Jul 2022 04:32:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232724AbiGLIc3 (ORCPT ); Tue, 12 Jul 2022 04:32:29 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 94CF7A5E55 for ; Tue, 12 Jul 2022 01:32:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1657614729; 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: in-reply-to:in-reply-to:references:references; bh=tQxIBj6PcKC66/v1neohOf1D/KG+opt9mK5QyhmwE5w=; b=Z6cwDODOb4PxM9FKaLNotLpBIjTfuxVxCwKqpW/jrVTZO7y531yK+TO1XZHgKPsb+w4JIo 8uFc6Nf4cDwlErMbJHVnCch1yjm5G/o/XUfTabyZQiYWepxqZIMfOZG+tNJBZLJ4gqpAjy ksILufxKoJKqeQ0Qq5LGAM1loU3xDZA= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-16-97XA7a_IMQmseuEGgQzkuw-1; Tue, 12 Jul 2022 04:32:00 -0400 X-MC-Unique: 97XA7a_IMQmseuEGgQzkuw-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 087E1185A7B2; Tue, 12 Jul 2022 08:32:00 +0000 (UTC) Received: from sirius.home.kraxel.org (unknown [10.39.192.39]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C06E8492C3B; Tue, 12 Jul 2022 08:31:59 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id EF3FC18000A9; Tue, 12 Jul 2022 10:31:57 +0200 (CEST) Date: Tue, 12 Jul 2022 10:31:57 +0200 From: Gerd Hoffmann To: Geert Uytterhoeven Cc: Linux Fbdev development list , Thomas Zimmermann , Michel =?utf-8?Q?D=C3=A4nzer?= , David Airlie , Linux/m68k , Linux Kernel Mailing List , Noralf =?utf-8?Q?Tr=C3=B8nnes?= , DRI Development Subject: Re: [PATCH 1/3] drm/fourcc: Add missing big-endian XRGB1555 and RGB565 formats Message-ID: <20220712083157.wtujadjcyboerxcl@sirius.home.kraxel.org> References: <0744671ac096a12f0d538906bd324efa71b11400.1657300532.git.geert@linux-m68k.org> <96a87833-d878-dde9-e335-9ea51a4ba406@mailbox.org> <20220712074715.kopstlvz4q6npaye@sirius.home.kraxel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220712074715.kopstlvz4q6npaye@sirius.home.kraxel.org> X-Scanned-By: MIMEDefang 2.85 on 10.11.54.10 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, > So adding support for bigendian formats to the driver shouldn't be > much of a problem. The vram will continue to run in little endian > RGB565, the shadow will be big endian RGB565, and the driver must > byteswap when copying. For completeness: The other obvious option (for fbcon) would be to handle the byteswapping in the generic drm fbdev emulation, which would have the advantage that it would be more generic and would not depend on the drm driver supporting the bigendian rgb565 formats ... take care, Gerd