From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Subject: Re: [PATCH] drm: fourcc byteorder: brings header file comments in line with reality. Date: Fri, 21 Apr 2017 14:08:04 +0300 Message-ID: <20170421110804.GH30290@intel.com> References: <20170421075825.6307-1-kraxel@redhat.com> <20170421092530.GE30290@intel.com> <1492768218.25675.33.camel@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Content-Disposition: inline In-Reply-To: <1492768218.25675.33.camel@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Gerd Hoffmann Cc: Michel =?iso-8859-1?Q?D=E4nzer?= , open list , dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, Daniel Vetter List-Id: amd-gfx.lists.freedesktop.org T24gRnJpLCBBcHIgMjEsIDIwMTcgYXQgMTE6NTA6MThBTSArMDIwMCwgR2VyZCBIb2ZmbWFubiB3 cm90ZToKPiBPbiBGciwgMjAxNy0wNC0yMSBhdCAxMjoyNSArMDMwMCwgVmlsbGUgU3lyasOkbMOk IHdyb3RlOgo+ID4gT24gRnJpLCBBcHIgMjEsIDIwMTcgYXQgMDk6NTg6MjRBTSArMDIwMCwgR2Vy ZCBIb2ZmbWFubiB3cm90ZToKPiA+ID4gV2hpbGUgd29ya2luZyBvbiBncmFwaGljcyBzdXBwb3J0 IGZvciB2aXJ0dWFsIG1hY2hpbmVzIG9uIHBwYzY0ICh3aGljaAo+ID4gPiBleGlzdHMgaW4gYm90 aCBsaXR0bGUgYW5kIGJpZyBlbmRpYW4gdmFyaWFudHMpIEkndmUgZmlndXJlZCB0aGUgY29tbWVu dHMKPiA+ID4gZm9yIHZhcmlvdXMgZHJtIGZvdXJjYyBmb3JtYXRzIGluIHRoZSBoZWFkZXIgZmls ZSBkb24ndCBtYXRjaCByZWFsaXR5Lgo+ID4gPiAKPiA+ID4gQ29tbWVudHMgc2F5cyB0aGUgUkdC IGZvcm1hdHMgYXJlIGxpdHRsZSBlbmRpYW4sIGJ1dCBpbiBwcmFjdGljZSB0aGV5Cj4gPiA+IGFy ZSBuYXRpdmUgZW5kaWFuLiAgTG9vayBhdCB0aGUgZHJtX21vZGVfbGVnYWN5X2ZiX2Zvcm1hdCgp IGhlbHBlci4gIEl0Cj4gPiA+IG1hcHMgLS0gZm9yIGV4YW1wbGUgLS0gYnBwL2RlcHRoIDMyLzI0 IHRvIERSTV9GT1JNQVRfWFJHQjg4ODgsIG5vIG1hdHRlcgo+ID4gPiB3aGVuZXZlciB0aGUgbWFj aGluZSBpcyBsaXR0bGUgZW5kaWFuIG9yIGJpZyBlbmRpYW4uICBUaGUgdXNlcnMgb2YgdGhpcwo+ ID4gPiBmdW5jdGlvbiAoZmJkZXYgZW11bGF0aW9uLCBEUk1fSU9DVExfTU9ERV9BRERGQikgZXhw ZWN0IHRoZSBmcmFtZWJ1ZmZlcgo+ID4gPiBpcyBuYXRpdmUgZW5kaWFuLCBub3QgbGl0dGxlIGVu ZGlhbi4gIE1vc3QgdXNlcnNwYWNlIGFsc28gb3BlcmF0ZXMgb24KPiA+ID4gbmF0aXZlIGVuZGlh biBvbmx5Lgo+ID4gCj4gPiBJJ20gbm90IGEgZmFuIG9mICJuYXRpdmUiLiBOYXRpdmUgdG8gd2hh dD8gIkNQVSIgb3IgImhvc3QiIGlzIHdoYXQgSSdkCj4gPiBjYWxsIGl0Lgo+IAo+IG5hdGl2ZSA9 PSB3aGF0ZXZlciB0aGUgY3B1IGlzIHVzaW5nLgo+IAo+IEkgcGVyc29uYWxseSBmaW5kICJuYXRp dmUiIG1vcmUgaW50dWl0aXZlLCBidXQgYXQgdGhlIGVuZCBvZiB0aGUgZGF5IEkKPiBkb24ndCBt aW5kIG11Y2guICBJZiBwZW9wbGUgcHJlZmVyICJob3N0IiBvdmVyICJuYXRpdmUiIEknbGwgY2hh bmdlIGl0LgoKIm5hdGl2ZSIgdG8gbWUgZmVlbHMgbW9yZSBsaWtlICJuYXRpdmUgdG8gdGhlIEdQ VSIgc2luY2UgdGhlc2UgdGhpbmdzCnJlYWxseSBhcmUgdGllZCB0byB0aGUgR1BVIG5vdCB0aGUg Q1BVLiBUaGF0J3MgYWxzbyB3aHkgSSB3ZW50IHdpdGggdGhlCmV4cGxpY2l0IGVuZGlhbm5lc3Mg b3JpZ2luYWxseSBzbyB0aGF0IHRoZSBkcml2ZXIgY291bGQgcHJvcGVybHkgZGVjbGFyZQp3aGF0 IHRoZSBHUFUgc3VwcG9ydHMuCgotLSAKVmlsbGUgU3lyasOkbMOkCkludGVsIE9UQwpfX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpkcmktZGV2ZWwgbWFpbGlu ZyBsaXN0CmRyaS1kZXZlbEBsaXN0cy5mcmVlZGVza3RvcC5vcmcKaHR0cHM6Ly9saXN0cy5mcmVl ZGVza3RvcC5vcmcvbWFpbG1hbi9saXN0aW5mby9kcmktZGV2ZWwK From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1038474AbdDULIN (ORCPT ); Fri, 21 Apr 2017 07:08:13 -0400 Received: from mga03.intel.com ([134.134.136.65]:44010 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1035411AbdDULIK (ORCPT ); Fri, 21 Apr 2017 07:08:10 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.37,229,1488873600"; d="scan'208";a="1159209851" Date: Fri, 21 Apr 2017 14:08:04 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Gerd Hoffmann Cc: dri-devel@lists.freedesktop.org, Daniel Vetter , Pekka Paalanen , Ilia Mirkin , 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: <20170421110804.GH30290@intel.com> References: <20170421075825.6307-1-kraxel@redhat.com> <20170421092530.GE30290@intel.com> <1492768218.25675.33.camel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1492768218.25675.33.camel@redhat.com> 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 On Fri, Apr 21, 2017 at 11:50:18AM +0200, Gerd Hoffmann wrote: > 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. "native" to me feels more like "native to the GPU" since these things really are tied to the GPU not the CPU. That's also why I went with the explicit endianness originally so that the driver could properly declare what the GPU supports. -- Ville Syrjälä Intel OTC