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

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Gerd Hoffmann <kraxel@redhat.com>
Cc: "Pekka Paalanen" <ppaalanen@gmail.com>,
	dri-devel@lists.freedesktop.org,
	"Daniel Vetter" <daniel.vetter@intel.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 12:44:49 +0300	[thread overview]
Message-ID: <20170421094449.GF30290@intel.com> (raw)
In-Reply-To: <1492767508.25675.23.camel@redhat.com>

On Fri, Apr 21, 2017 at 11:38:28AM +0200, Gerd Hoffmann wrote:
>   Hi,
> 
> > > Leaving the yuv formats as-is.  I have no idea if and how those are used
> > > on bigendian machines.
> 
> > just an idea - since we are not sure how the remaining formats are being
> > used, should those be marked somehow uncertain whether they are little
> > or native endian?
> 
> ATM the yuv don't have any byte order annotations, and I simply left
> them that way.  So it is as clear/unclear as before.

Eh? Everything that is affected by byte order has the relevant comments.
If they don't, then that's a bug.

> 
> IIRC someone mentioned that for the yuv fourccs there actually is some
> standard about the exact ordering.  Anyone has a good reference?  We
> could stick a link to it into a comment.

The "standard" is fourcc. Whether there is any official reference for
that is unclear. That's exactly why I added the explicit comments into
drm_fourcc.h so that people don't have to go trawling the internets
looking for information on what each pixel format might mean.

-- 
Ville Syrjälä
Intel OTC