Re: [PATCH] drm: fourcc byteorder: brings header file comments in line with reality.

From	Michel Dänzer <michel@daenzer.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH] drm: fourcc byteorder: brings header file comments in line with reality.
Date	2017-04-24 08:40 +0200
Message-ID	<tzFPc-3wO-15@gated-at.bofh.it> (permalink)
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On 23/04/17 04:24 AM, Ilia Mirkin wrote:
> 
> fbdev also creates fb's that expect cpu endianness, as disabling the
> byteswap logic caused a green fbcon terminal to show up. (So at least
> something somewhere in the fbcon -> nouveau's fbdev emulation pipeline
> is expecting cpu endianness. This happens both with nouveau's fbdev
> accel logic and without.)

In theory, there's FB_FOREIGN_ENDIAN for that. But in practice it's
probably useless because little if any userspace even checks for it, let
alone handles it correctly.

> So I think the current situation, at least wrt pre-nv50 nouveau, is
> that XRGB/ARGB8888 are "special", since they are the only things
> exposed by drm_crtc_init. I believe those definitions should be
> updated to note that they're cpu-endian-specific (or another way of
> phrasing it more diplomatically is that they're array formats rather
> than packed formats).

That would be incorrect. :) The memory layout of 8-bit-per-component
array formats doesn't depend on endianness, that of packed formats does.
(DRM_FORMAT_*8 as currently defined are thus effectively array formats)

-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer

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[PATCH] drm: fourcc byteorder: brings header file comments in line with reality. Gerd Hoffmann <kraxel@redhat.com> - 2017-04-21 10:00 +0200
  Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Pekka Paalanen <ppaalanen@gmail.com> - 2017-04-21 10:10 +0200
    Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Gerd Hoffmann <kraxel@redhat.com> - 2017-04-21 11:40 +0200
      Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Ville Syrjälä <ville.syrjala@linux.intel.com> - 2017-04-21 11:50 +0200
  Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Ville Syrjälä <ville.syrjala@linux.intel.com> - 2017-04-21 11:30 +0200
    Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Gerd Hoffmann <kraxel@redhat.com> - 2017-04-21 12:00 +0200
      Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Ville Syrjälä <ville.syrjala@linux.intel.com> - 2017-04-21 13:10 +0200
        Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Gerd Hoffmann <kraxel@redhat.com> - 2017-04-21 13:50 +0200
        Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Pekka Paalanen <ppaalanen@gmail.com> - 2017-04-21 13:50 +0200
          Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Ville Syrjälä <ville.syrjala@linux.intel.com> - 2017-04-21 13:50 +0200
        Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Gerd Hoffmann <kraxel@redhat.com> - 2017-04-21 15:20 +0200
          Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Christian König <deathsimple@vodafone.de> - 2017-04-21 15:30 +0200
          Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Gerd Hoffmann <kraxel@redhat.com> - 2017-04-21 23:40 +0200
            Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Ville Syrjälä <ville.syrjala@linux.intel.com> - 2017-04-22 12:10 +0200
              Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Gerd Hoffmann <kraxel@redhat.com> - 2017-04-23 00:00 +0200
              Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Michel Dänzer <michel@daenzer.net> - 2017-04-24 09:00 +0200
                Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Ville Syrjälä <ville.syrjala@linux.intel.com> - 2017-04-24 15:10 +0200
      Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Ville Syrjälä <ville.syrjala@linux.intel.com> - 2017-04-21 13:10 +0200
  Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Ilia Mirkin <imirkin@alum.mit.edu> - 2017-04-21 17:30 +0200
    Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Ville Syrjälä <ville.syrjala@linux.intel.com> - 2017-04-21 20:20 +0200
      Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Ilia Mirkin <imirkin@alum.mit.edu> - 2017-04-22 07:10 +0200
        Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Ville Syrjälä <ville.syrjala@linux.intel.com> - 2017-04-22 12:00 +0200
          Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Ilia Mirkin <imirkin@alum.mit.edu> - 2017-04-22 15:50 +0200
            Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Ilia Mirkin <imirkin@alum.mit.edu> - 2017-04-22 15:50 +0200
              Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Ilia Mirkin <imirkin@alum.mit.edu> - 2017-04-22 21:30 +0200
                Re: [PATCH] drm: fourcc byteorder: brings header file comments in  line with reality. Michel Dänzer <michel@daenzer.net> - 2017-04-24 08:40 +0200

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