From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Subject: Re: [PATCH 2/2] drm: Redefine pixel formats Date: Thu, 17 Nov 2011 15:06:58 +0200 Message-ID: <20111117130658.GT3477@intel.com> References: <1321468945-28224-1-git-send-email-ville.syrjala@linux.intel.com> <1321468945-28224-3-git-send-email-ville.syrjala@linux.intel.com> <1321516325.3794.60.camel@thor.local> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by gabe.freedesktop.org (Postfix) with ESMTP id 2889C9F104 for ; Thu, 17 Nov 2011 05:04:35 -0800 (PST) Content-Disposition: inline In-Reply-To: <1321516325.3794.60.camel@thor.local> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org Errors-To: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org To: Michel =?iso-8859-1?Q?D=E4nzer?= Cc: dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org On Thu, Nov 17, 2011 at 08:52:05AM +0100, Michel D=E4nzer wrote: > On Mit, 2011-11-16 at 20:42 +0200, ville.syrjala@linux.intel.com wrote: = > > = > > Name the formats as DRM_FORMAT_X instead of DRM_FOURCC_X. Use consistent > > names, especially for the RGB formats. Component order and byte order a= re > > now strictly specified for each format. > > = > > The RGB format naming follows a convention where the components names > > and sizes are listed from left to right, matching the order within a > > single pixel from most significant bit to least significant bit. Lower > > case letters are used when listing the components to improve > > readablility. I believe this convention matches the one used by pixman. > = > The RGB formats are all defined in the CPU native byte order. But e.g. > pre-R600 Radeons can only scan out little endian formats. For the > framebuffer device, we use GPU byte swapping facilities to make the > pixels appear to the CPU in its native byte order, so these format > definitions make sense for that. But I'm not sure they make sense for > the KMS APIs, e.g. the userspace drivers don't use these facilities but > handle byte swapping themselves. Hmm. So who decides whether GPU byte swapping is needed when you eg. mmap() some buffer? -- = Ville Syrj=E4l=E4 Intel OTC