From: Gerd Hoffmann <kraxel@redhat.com>
To: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: dri-devel@lists.freedesktop.org,
"Daniel Vetter" <daniel.vetter@intel.com>,
"Pekka Paalanen" <ppaalanen@gmail.com>,
"Ilia Mirkin" <imirkin@alum.mit.edu>,
"Michel Dänzer" <michel@daenzer.net>,
"Alex Deucher" <alexdeucher@gmail.com>,
amd-gfx@lists.freedesktop.org,
"Jani Nikula" <jani.nikula@linux.intel.com>,
"Sean Paul" <seanpaul@chromium.org>,
"David Airlie" <airlied@linux.ie>,
"open list" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] drm: fourcc byteorder: brings header file comments in line with reality.
Date: Fri, 21 Apr 2017 11:50:18 +0200 [thread overview]
Message-ID: <1492768218.25675.33.camel@redhat.com> (raw)
In-Reply-To: <20170421092530.GE30290@intel.com>
On Fr, 2017-04-21 at 12:25 +0300, Ville Syrjälä wrote:
> On Fri, Apr 21, 2017 at 09:58:24AM +0200, 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.
>
> I'm not a fan of "native". Native to what? "CPU" or "host" is what I'd
> call it.
native == whatever the cpu is using.
I personally find "native" more intuitive, but at the end of the day I
don't mind much. If people prefer "host" over "native" I'll change it.
> And what about the mxied endian case? Are you just going to pretend it
> doesn't exist or what?
What exactly do you mean with "mixed endian"? The powerpc case, where
kernel + userspace can run in either big or little endian mode? Or
something else?
cheers,
Gerd
next prev parent reply other threads:[~2017-04-21 9:50 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-21 7:58 [PATCH] drm: fourcc byteorder: brings header file comments in line with reality Gerd Hoffmann
2017-04-21 8:06 ` Pekka Paalanen
2017-04-21 9:38 ` Gerd Hoffmann
2017-04-21 9:44 ` Ville Syrjälä
2017-04-21 9:25 ` Ville Syrjälä
2017-04-21 9:50 ` Gerd Hoffmann [this message]
2017-04-21 11:05 ` Ville Syrjälä
2017-04-21 11:08 ` Ville Syrjälä
2017-04-21 11:40 ` Pekka Paalanen
2017-04-21 11:49 ` Ville Syrjälä
2017-04-21 12:02 ` Christian König
2017-04-21 11:41 ` Gerd Hoffmann
2017-04-21 11:42 ` Christian König
2017-04-21 13:12 ` Gerd Hoffmann
2017-04-21 13:21 ` Christian König
2017-04-21 13:27 ` Christian König
2017-04-21 15:21 ` Harry Wentland
2017-04-21 16:14 ` Gerd Hoffmann
2017-04-22 10:05 ` Ville Syrjälä
2017-04-22 21:59 ` Gerd Hoffmann
2017-04-24 6:57 ` Michel Dänzer
2017-04-24 13:03 ` Ville Syrjälä
2017-04-25 1:12 ` Michel Dänzer
2017-04-25 3:08 ` Michel Dänzer
2017-04-25 10:26 ` Ville Syrjälä
2017-04-26 2:10 ` Michel Dänzer
2017-05-11 21:23 ` Pavel Machek
2017-05-12 9:10 ` Ville Syrjälä
2017-04-21 14:49 ` Ilia Mirkin
2017-04-21 16:59 ` Ville Syrjälä
2017-04-22 5:07 ` Ilia Mirkin
2017-04-22 9:50 ` Ville Syrjälä
2017-04-22 13:40 ` Ilia Mirkin
2017-04-22 13:48 ` Ilia Mirkin
2017-04-22 19:24 ` Ilia Mirkin
2017-04-24 6:33 ` Michel Dänzer
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