Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423389AbdDUSI0 (ORCPT ); Fri, 21 Apr 2017 14:08:26 -0400 Received: from mga07.intel.com ([134.134.136.100]:14312 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423360AbdDUSIF (ORCPT ); Fri, 21 Apr 2017 14:08:05 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.37,230,1488873600"; d="scan'208";a="1138643951" Date: Fri, 21 Apr 2017 19:59:07 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Ilia Mirkin Cc: Gerd Hoffmann , "dri-devel@lists.freedesktop.org" , Daniel Vetter , Pekka Paalanen , Michel =?iso-8859-1?Q?D=E4nzer?= , Alex Deucher , amd-gfx@lists.freedesktop.org, Jani Nikula , Sean Paul , David Airlie , open list Subject: Re: [PATCH] drm: fourcc byteorder: brings header file comments in line with reality. Message-ID: <20170421165907.GQ30290@intel.com> References: <20170421075825.6307-1-kraxel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 13098 Lines: 191 On Fri, Apr 21, 2017 at 10:49:49AM -0400, Ilia Mirkin wrote: > On Fri, Apr 21, 2017 at 3:58 AM, Gerd Hoffmann wrote: > > While working on graphics support for virtual machines on ppc64 (which > > exists in both little and big endian variants) I've figured the comments > > for various drm fourcc formats in the header file don't match reality. > > > > Comments says the RGB formats are little endian, but in practice they > > are native endian. Look at the drm_mode_legacy_fb_format() helper. It > > maps -- for example -- bpp/depth 32/24 to DRM_FORMAT_XRGB8888, no matter > > whenever the machine is little endian or big endian. The users of this > > function (fbdev emulation, DRM_IOCTL_MODE_ADDFB) expect the framebuffer > > is native endian, not little endian. Most userspace also operates on > > native endian only. > > > > So, go update the comments for all 16+24+32 bpp RGB formats. > > > > Leaving the yuv formats as-is. I have no idea if and how those are used > > on bigendian machines. > > I think this is premature. The current situation is that I can't get > modetest to work *at all* on my NV34 / BE setup (I mean, it runs, just > the colors displayed are wrong). I believe that currently it packs > things in "cpu native endian". I've tried futzing with that without > much success, although I didn't spend too much time on it. I have a > NV34 plugged into my LE setup as well although I haven't tested to > double-check that it all works there. However I'm quite sure it used > to, as I used modetest to help develop the YUV overlay support for > those GPUs. I just took a quick stab at fixing modetest to respect the current wording in drm_fourcc.h: git://github.com/vsyrjala/libdrm.git modetest_endian > > Does modetest work for you, under any interpretation of the formats? > > There's an additional complication wrt looking at what fbcon does, > since it will feed the data in via special accel interfaces in fbdev, > which at least on nouveau, may end up byteswapping the data on upload > to VRAM (I'm not 100% clear on whether they do or not). However > modetest, which is creating its own fb, likely won't get such > treatment. > > This is a shitty situation - we have hardware we don't know how it > works, tools we don't know whether they're broken, and comments we're > pretty sure are at least somewhat wrong. Furthermore the hardware is > relatively rare and developers with time to work on improving it are > even rarer. > > I'd like to reiterate that the status quo does end up in a functioning > system. Let's try not to break that. > > Cheers, > > -ilia > > > > > Cc: Ville Syrj?l? > > Cc: Daniel Vetter > > Cc: Pekka Paalanen > > Cc: Ilia Mirkin > > Cc: Michel D?nzer > > Cc: Alex Deucher > > Cc: amd-gfx@lists.freedesktop.org > > Signed-off-by: Gerd Hoffmann > > --- > > include/uapi/drm/drm_fourcc.h | 82 +++++++++++++++++++++---------------------- > > 1 file changed, 41 insertions(+), 41 deletions(-) > > > > diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h > > index 995c8f9..1579765 100644 > > --- a/include/uapi/drm/drm_fourcc.h > > +++ b/include/uapi/drm/drm_fourcc.h > > @@ -42,68 +42,68 @@ extern "C" { > > #define DRM_FORMAT_R8 fourcc_code('R', '8', ' ', ' ') /* [7:0] R */ > > > > /* 16 bpp Red */ > > -#define DRM_FORMAT_R16 fourcc_code('R', '1', '6', ' ') /* [15:0] R little endian */ > > +#define DRM_FORMAT_R16 fourcc_code('R', '1', '6', ' ') /* [15:0] R native endian */ > > > > /* 16 bpp RG */ > > -#define DRM_FORMAT_RG88 fourcc_code('R', 'G', '8', '8') /* [15:0] R:G 8:8 little endian */ > > -#define DRM_FORMAT_GR88 fourcc_code('G', 'R', '8', '8') /* [15:0] G:R 8:8 little endian */ > > +#define DRM_FORMAT_RG88 fourcc_code('R', 'G', '8', '8') /* [15:0] R:G 8:8 native endian */ > > +#define DRM_FORMAT_GR88 fourcc_code('G', 'R', '8', '8') /* [15:0] G:R 8:8 native endian */ > > > > /* 32 bpp RG */ > > -#define DRM_FORMAT_RG1616 fourcc_code('R', 'G', '3', '2') /* [31:0] R:G 16:16 little endian */ > > -#define DRM_FORMAT_GR1616 fourcc_code('G', 'R', '3', '2') /* [31:0] G:R 16:16 little endian */ > > +#define DRM_FORMAT_RG1616 fourcc_code('R', 'G', '3', '2') /* [31:0] R:G 16:16 native endian */ > > +#define DRM_FORMAT_GR1616 fourcc_code('G', 'R', '3', '2') /* [31:0] G:R 16:16 native endian */ > > > > /* 8 bpp RGB */ > > #define DRM_FORMAT_RGB332 fourcc_code('R', 'G', 'B', '8') /* [7:0] R:G:B 3:3:2 */ > > #define DRM_FORMAT_BGR233 fourcc_code('B', 'G', 'R', '8') /* [7:0] B:G:R 2:3:3 */ > > > > /* 16 bpp RGB */ > > -#define DRM_FORMAT_XRGB4444 fourcc_code('X', 'R', '1', '2') /* [15:0] x:R:G:B 4:4:4:4 little endian */ > > -#define DRM_FORMAT_XBGR4444 fourcc_code('X', 'B', '1', '2') /* [15:0] x:B:G:R 4:4:4:4 little endian */ > > -#define DRM_FORMAT_RGBX4444 fourcc_code('R', 'X', '1', '2') /* [15:0] R:G:B:x 4:4:4:4 little endian */ > > -#define DRM_FORMAT_BGRX4444 fourcc_code('B', 'X', '1', '2') /* [15:0] B:G:R:x 4:4:4:4 little endian */ > > +#define DRM_FORMAT_XRGB4444 fourcc_code('X', 'R', '1', '2') /* [15:0] x:R:G:B 4:4:4:4 native endian */ > > +#define DRM_FORMAT_XBGR4444 fourcc_code('X', 'B', '1', '2') /* [15:0] x:B:G:R 4:4:4:4 native endian */ > > +#define DRM_FORMAT_RGBX4444 fourcc_code('R', 'X', '1', '2') /* [15:0] R:G:B:x 4:4:4:4 native endian */ > > +#define DRM_FORMAT_BGRX4444 fourcc_code('B', 'X', '1', '2') /* [15:0] B:G:R:x 4:4:4:4 native endian */ > > > > -#define DRM_FORMAT_ARGB4444 fourcc_code('A', 'R', '1', '2') /* [15:0] A:R:G:B 4:4:4:4 little endian */ > > -#define DRM_FORMAT_ABGR4444 fourcc_code('A', 'B', '1', '2') /* [15:0] A:B:G:R 4:4:4:4 little endian */ > > -#define DRM_FORMAT_RGBA4444 fourcc_code('R', 'A', '1', '2') /* [15:0] R:G:B:A 4:4:4:4 little endian */ > > -#define DRM_FORMAT_BGRA4444 fourcc_code('B', 'A', '1', '2') /* [15:0] B:G:R:A 4:4:4:4 little endian */ > > +#define DRM_FORMAT_ARGB4444 fourcc_code('A', 'R', '1', '2') /* [15:0] A:R:G:B 4:4:4:4 native endian */ > > +#define DRM_FORMAT_ABGR4444 fourcc_code('A', 'B', '1', '2') /* [15:0] A:B:G:R 4:4:4:4 native endian */ > > +#define DRM_FORMAT_RGBA4444 fourcc_code('R', 'A', '1', '2') /* [15:0] R:G:B:A 4:4:4:4 native endian */ > > +#define DRM_FORMAT_BGRA4444 fourcc_code('B', 'A', '1', '2') /* [15:0] B:G:R:A 4:4:4:4 native endian */ > > > > -#define DRM_FORMAT_XRGB1555 fourcc_code('X', 'R', '1', '5') /* [15:0] x:R:G:B 1:5:5:5 little endian */ > > -#define DRM_FORMAT_XBGR1555 fourcc_code('X', 'B', '1', '5') /* [15:0] x:B:G:R 1:5:5:5 little endian */ > > -#define DRM_FORMAT_RGBX5551 fourcc_code('R', 'X', '1', '5') /* [15:0] R:G:B:x 5:5:5:1 little endian */ > > -#define DRM_FORMAT_BGRX5551 fourcc_code('B', 'X', '1', '5') /* [15:0] B:G:R:x 5:5:5:1 little endian */ > > +#define DRM_FORMAT_XRGB1555 fourcc_code('X', 'R', '1', '5') /* [15:0] x:R:G:B 1:5:5:5 native endian */ > > +#define DRM_FORMAT_XBGR1555 fourcc_code('X', 'B', '1', '5') /* [15:0] x:B:G:R 1:5:5:5 native endian */ > > +#define DRM_FORMAT_RGBX5551 fourcc_code('R', 'X', '1', '5') /* [15:0] R:G:B:x 5:5:5:1 native endian */ > > +#define DRM_FORMAT_BGRX5551 fourcc_code('B', 'X', '1', '5') /* [15:0] B:G:R:x 5:5:5:1 native endian */ > > > > -#define DRM_FORMAT_ARGB1555 fourcc_code('A', 'R', '1', '5') /* [15:0] A:R:G:B 1:5:5:5 little endian */ > > -#define DRM_FORMAT_ABGR1555 fourcc_code('A', 'B', '1', '5') /* [15:0] A:B:G:R 1:5:5:5 little endian */ > > -#define DRM_FORMAT_RGBA5551 fourcc_code('R', 'A', '1', '5') /* [15:0] R:G:B:A 5:5:5:1 little endian */ > > -#define DRM_FORMAT_BGRA5551 fourcc_code('B', 'A', '1', '5') /* [15:0] B:G:R:A 5:5:5:1 little endian */ > > +#define DRM_FORMAT_ARGB1555 fourcc_code('A', 'R', '1', '5') /* [15:0] A:R:G:B 1:5:5:5 native endian */ > > +#define DRM_FORMAT_ABGR1555 fourcc_code('A', 'B', '1', '5') /* [15:0] A:B:G:R 1:5:5:5 native endian */ > > +#define DRM_FORMAT_RGBA5551 fourcc_code('R', 'A', '1', '5') /* [15:0] R:G:B:A 5:5:5:1 native endian */ > > +#define DRM_FORMAT_BGRA5551 fourcc_code('B', 'A', '1', '5') /* [15:0] B:G:R:A 5:5:5:1 native endian */ > > > > -#define DRM_FORMAT_RGB565 fourcc_code('R', 'G', '1', '6') /* [15:0] R:G:B 5:6:5 little endian */ > > -#define DRM_FORMAT_BGR565 fourcc_code('B', 'G', '1', '6') /* [15:0] B:G:R 5:6:5 little endian */ > > +#define DRM_FORMAT_RGB565 fourcc_code('R', 'G', '1', '6') /* [15:0] R:G:B 5:6:5 native endian */ > > +#define DRM_FORMAT_BGR565 fourcc_code('B', 'G', '1', '6') /* [15:0] B:G:R 5:6:5 native endian */ > > > > /* 24 bpp RGB */ > > -#define DRM_FORMAT_RGB888 fourcc_code('R', 'G', '2', '4') /* [23:0] R:G:B little endian */ > > -#define DRM_FORMAT_BGR888 fourcc_code('B', 'G', '2', '4') /* [23:0] B:G:R little endian */ > > +#define DRM_FORMAT_RGB888 fourcc_code('R', 'G', '2', '4') /* [23:0] R:G:B native endian */ > > +#define DRM_FORMAT_BGR888 fourcc_code('B', 'G', '2', '4') /* [23:0] B:G:R native endian */ > > > > /* 32 bpp RGB */ > > -#define DRM_FORMAT_XRGB8888 fourcc_code('X', 'R', '2', '4') /* [31:0] x:R:G:B 8:8:8:8 little endian */ > > -#define DRM_FORMAT_XBGR8888 fourcc_code('X', 'B', '2', '4') /* [31:0] x:B:G:R 8:8:8:8 little endian */ > > -#define DRM_FORMAT_RGBX8888 fourcc_code('R', 'X', '2', '4') /* [31:0] R:G:B:x 8:8:8:8 little endian */ > > -#define DRM_FORMAT_BGRX8888 fourcc_code('B', 'X', '2', '4') /* [31:0] B:G:R:x 8:8:8:8 little endian */ > > +#define DRM_FORMAT_XRGB8888 fourcc_code('X', 'R', '2', '4') /* [31:0] x:R:G:B 8:8:8:8 native endian */ > > +#define DRM_FORMAT_XBGR8888 fourcc_code('X', 'B', '2', '4') /* [31:0] x:B:G:R 8:8:8:8 native endian */ > > +#define DRM_FORMAT_RGBX8888 fourcc_code('R', 'X', '2', '4') /* [31:0] R:G:B:x 8:8:8:8 native endian */ > > +#define DRM_FORMAT_BGRX8888 fourcc_code('B', 'X', '2', '4') /* [31:0] B:G:R:x 8:8:8:8 native endian */ > > > > -#define DRM_FORMAT_ARGB8888 fourcc_code('A', 'R', '2', '4') /* [31:0] A:R:G:B 8:8:8:8 little endian */ > > -#define DRM_FORMAT_ABGR8888 fourcc_code('A', 'B', '2', '4') /* [31:0] A:B:G:R 8:8:8:8 little endian */ > > -#define DRM_FORMAT_RGBA8888 fourcc_code('R', 'A', '2', '4') /* [31:0] R:G:B:A 8:8:8:8 little endian */ > > -#define DRM_FORMAT_BGRA8888 fourcc_code('B', 'A', '2', '4') /* [31:0] B:G:R:A 8:8:8:8 little endian */ > > +#define DRM_FORMAT_ARGB8888 fourcc_code('A', 'R', '2', '4') /* [31:0] A:R:G:B 8:8:8:8 native endian */ > > +#define DRM_FORMAT_ABGR8888 fourcc_code('A', 'B', '2', '4') /* [31:0] A:B:G:R 8:8:8:8 native endian */ > > +#define DRM_FORMAT_RGBA8888 fourcc_code('R', 'A', '2', '4') /* [31:0] R:G:B:A 8:8:8:8 native endian */ > > +#define DRM_FORMAT_BGRA8888 fourcc_code('B', 'A', '2', '4') /* [31:0] B:G:R:A 8:8:8:8 native endian */ > > > > -#define DRM_FORMAT_XRGB2101010 fourcc_code('X', 'R', '3', '0') /* [31:0] x:R:G:B 2:10:10:10 little endian */ > > -#define DRM_FORMAT_XBGR2101010 fourcc_code('X', 'B', '3', '0') /* [31:0] x:B:G:R 2:10:10:10 little endian */ > > -#define DRM_FORMAT_RGBX1010102 fourcc_code('R', 'X', '3', '0') /* [31:0] R:G:B:x 10:10:10:2 little endian */ > > -#define DRM_FORMAT_BGRX1010102 fourcc_code('B', 'X', '3', '0') /* [31:0] B:G:R:x 10:10:10:2 little endian */ > > +#define DRM_FORMAT_XRGB2101010 fourcc_code('X', 'R', '3', '0') /* [31:0] x:R:G:B 2:10:10:10 native endian */ > > +#define DRM_FORMAT_XBGR2101010 fourcc_code('X', 'B', '3', '0') /* [31:0] x:B:G:R 2:10:10:10 native endian */ > > +#define DRM_FORMAT_RGBX1010102 fourcc_code('R', 'X', '3', '0') /* [31:0] R:G:B:x 10:10:10:2 native endian */ > > +#define DRM_FORMAT_BGRX1010102 fourcc_code('B', 'X', '3', '0') /* [31:0] B:G:R:x 10:10:10:2 native endian */ > > > > -#define DRM_FORMAT_ARGB2101010 fourcc_code('A', 'R', '3', '0') /* [31:0] A:R:G:B 2:10:10:10 little endian */ > > -#define DRM_FORMAT_ABGR2101010 fourcc_code('A', 'B', '3', '0') /* [31:0] A:B:G:R 2:10:10:10 little endian */ > > -#define DRM_FORMAT_RGBA1010102 fourcc_code('R', 'A', '3', '0') /* [31:0] R:G:B:A 10:10:10:2 little endian */ > > -#define DRM_FORMAT_BGRA1010102 fourcc_code('B', 'A', '3', '0') /* [31:0] B:G:R:A 10:10:10:2 little endian */ > > +#define DRM_FORMAT_ARGB2101010 fourcc_code('A', 'R', '3', '0') /* [31:0] A:R:G:B 2:10:10:10 native endian */ > > +#define DRM_FORMAT_ABGR2101010 fourcc_code('A', 'B', '3', '0') /* [31:0] A:B:G:R 2:10:10:10 native endian */ > > +#define DRM_FORMAT_RGBA1010102 fourcc_code('R', 'A', '3', '0') /* [31:0] R:G:B:A 10:10:10:2 native endian */ > > +#define DRM_FORMAT_BGRA1010102 fourcc_code('B', 'A', '3', '0') /* [31:0] B:G:R:A 10:10:10:2 native endian */ > > > > /* packed YCbCr */ > > #define DRM_FORMAT_YUYV fourcc_code('Y', 'U', 'Y', 'V') /* [31:0] Cr0:Y1:Cb0:Y0 8:8:8:8 little endian */ > > -- > > 2.9.3 > > -- Ville Syrj?l? Intel OTC