Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757482AbdDRUuY convert rfc822-to-8bit (ORCPT ); Tue, 18 Apr 2017 16:50:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39830 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753509AbdDRUuV (ORCPT ); Tue, 18 Apr 2017 16:50:21 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 62C378FD08 Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=kraxel@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 62C378FD08 Message-ID: <1492548618.27392.72.camel@redhat.com> Subject: Re: [RfC PATCH] drm: fourcc byteorder: brings header file comments in line with reality. From: Gerd Hoffmann To: Pekka Paalanen Cc: dri-devel@lists.freedesktop.org, open list , amd-gfx@lists.freedesktop.org, Daniel Vetter , Ilia Mirkin Date: Tue, 18 Apr 2017 22:50:18 +0200 In-Reply-To: <20170418170134.0a60d340@eldfell> References: <20170410101202.19229-1-kraxel@redhat.com> <20170410161214.305f5daf@eldfell> <1491833847.30990.77.camel@redhat.com> <20170410180941.43922e25@eldfell> <1492509617.27392.19.camel@redhat.com> <20170418141827.11634103@eldfell> <1492522793.27392.55.camel@redhat.com> <20170418170134.0a60d340@eldfell> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Mime-Version: 1.0 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Tue, 18 Apr 2017 20:50:20 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1944 Lines: 50 Hi, > Right. Very nice if we can trust the virtual machine at least getting > things right, gives some chance for people to test anything. Except... > that's a question of what kind of hardware the virtual machine > emulates. The display device defines what endianess it uses on > framebuffers, not the CPU, right? The display device supports switching the endianess for the framebuffer, at least with kernel 3.19+ and qemu 2.2+. Default endianness depends on the machine type, i.e. ppc64 guests get a bigendian framebuffer and pretty much everything else a little endian framebuffer on reset. The bochs-drm driver switches the display into native endian mode, i.e. big endian for ppc64 and little endian for ppc64le kernels. See commit 9ecdb039b7517dc10b8c3e6dbeb40859178ac28e > > Well, I mean color glitches. But it isn't consistent. As if some > > operations operate with the correct byteorder and some don't. > > alpha/blue being swapped is a problem in some areas. > > > > https://www.kraxel.org/tmp/ > > Ooh, yeah, that's definitely bonkers. > > Maybe the 100% blue things are supposed to be a transparent blended > overlays, like highlights. > > The icons look somehow... not completely right to me. Somehow washed > out? > > Opaque gray shades are hard to tell right from wrong. > > gnome-terminal and the wallpaper look right, but those might be the > only things. > > Having a compositing manager complicates things. In some way yes, in some way no. Tried wayland meanwhile (using "gnome-shell --wayland"). Looks pretty much the same. Window decorations look a bit different (good on xorg, broken on wayland), probably because window decorations work completely different. Otherwise it is bug compatible to xorg. Probably because gnome-shell composites everything using llvmpipe, so it's largely the same code running on both xorg and wayland, which then finally scans out to a dumb framebuffer. cheers, Gerd