From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754773AbdBNUKB (ORCPT ); Tue, 14 Feb 2017 15:10:01 -0500 Received: from mail-yb0-f195.google.com ([209.85.213.195]:34520 "EHLO mail-yb0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754181AbdBNUJz (ORCPT ); Tue, 14 Feb 2017 15:09:55 -0500 Date: Tue, 14 Feb 2017 21:09:51 +0100 From: Daniel Vetter To: Daniel Stone Cc: Maxime Ripard , Daniel Vetter , Stefan Christ , Laurent Pinchart , dri-devel , Linux Kernel Mailing List Subject: Re: [PATCH v2 1/2] drm/cma-helper: Add multi buffer support for cma fbdev Message-ID: <20170214200951.GC22762@dvetter-linux.ger.corp.intel.com> Mail-Followup-To: Daniel Stone , Maxime Ripard , Daniel Vetter , Stefan Christ , Laurent Pinchart , dri-devel , Linux Kernel Mailing List References: <9b4f80f213b50959d168e6f22b21ee784fe26da5.1486031436.git-series.maxime.ripard@free-electrons.com> <2662533.Ps9k37FiVM@avalon> <20170213105422.2cfr7av6ha2vzdlk@lukather> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Operating-System: Linux dvetter-linux.ger.corp.intel.com 4.8.15-200.fc24.x86_64 User-Agent: Mutt/1.7.1 (2016-10-04) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 13, 2017 at 11:20:51AM +0000, Daniel Stone wrote: > Hi Maxime, > > On 13 February 2017 at 10:54, Maxime Ripard > wrote: > > On Sun, Feb 12, 2017 at 02:28:11PM +0200, Laurent Pinchart wrote: > >> On Thursday 02 Feb 2017 11:31:56 Maxime Ripard wrote: > >> > This patch add a config to support to create multi buffer for cma fbdev. > >> > Such as double buffer and triple buffer. > >> > > >> > Cma fbdev is convient to add a legency fbdev. And still many Android > >> > devices use fbdev now and at least double buffer is needed for these > >> > Android devices, so that a buffer flip can be operated. It will need > >> > some time for Android device vendors to abondon legency fbdev. So multi > >> > buffer for fbdev is needed. > >> > >> How exactly do we expect Android to move away from fbdev if we add features to > >> the fbdev compat layer ? I'd much rather make it clear to them that fbdev is a > >> thing from the past and that they'd better migrate now. > > > > If your point is that merging this patch will slow down the Android > > move away from fbdev, I disagree with that (obviously). > > > > I don't care at all about Android on my platform of choice, but don't > > see how that merging this patch will change anything. > > > > Let's be honest, Android trees typically have thousands of patches on > > top of mainline. Do you think a simple, 15 LoC, patch will make any > > difference to vendors? If they want to stay on fbdev and have that > > feature, they'll just merge this patch, done. > > So, in that case, why not just let them do that? They'd already have > to add patches to use this, surely; we don't have anything in mainline > kernels which allows people to actually use this larger allocation. > Apart from software mmap() and using panning to do flips, but I'm > taking it as a given that people shipping Android on their devices > aren't using software rendering. I think we need to make a distinction between fbdev the subsystem in the kernel, and fbdev the uabi: - fbdev the subsystem is completely dead in upstream. I think we have full agreement on that. - fbdev the uabi isn't, and if we can get more users from fbdev based drivers to kms/atomic drivers by adding fairly simple stuff like this, I'm all for it. Which means: Yes, I fully plan to merge this, it makes sense. It even _helps_ by making fbdev-the-subsystem even deader. Making live hard for out-of-tree folks or folks with shit userspace doesn't make sense, at least if the only benefit for us is that we'll feel pure about our intentions :-) Cheers, Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH v2 1/2] drm/cma-helper: Add multi buffer support for cma fbdev Date: Tue, 14 Feb 2017 21:09:51 +0100 Message-ID: <20170214200951.GC22762@dvetter-linux.ger.corp.intel.com> References: <9b4f80f213b50959d168e6f22b21ee784fe26da5.1486031436.git-series.maxime.ripard@free-electrons.com> <2662533.Ps9k37FiVM@avalon> <20170213105422.2cfr7av6ha2vzdlk@lukather> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Received: from mail-yb0-x241.google.com (mail-yb0-x241.google.com [IPv6:2607:f8b0:4002:c09::241]) by gabe.freedesktop.org (Postfix) with ESMTPS id 67D0D6E7FB for ; Tue, 14 Feb 2017 20:09:55 +0000 (UTC) Received: by mail-yb0-x241.google.com with SMTP id o65so6027561ybo.3 for ; Tue, 14 Feb 2017 12:09:55 -0800 (PST) Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Daniel Stone Cc: Linux Kernel Mailing List , dri-devel , Laurent Pinchart , Daniel Vetter , Maxime Ripard , Stefan Christ List-Id: dri-devel@lists.freedesktop.org T24gTW9uLCBGZWIgMTMsIDIwMTcgYXQgMTE6MjA6NTFBTSArMDAwMCwgRGFuaWVsIFN0b25lIHdy b3RlOgo+IEhpIE1heGltZSwKPiAKPiBPbiAxMyBGZWJydWFyeSAyMDE3IGF0IDEwOjU0LCBNYXhp bWUgUmlwYXJkCj4gPG1heGltZS5yaXBhcmRAZnJlZS1lbGVjdHJvbnMuY29tPiB3cm90ZToKPiA+ IE9uIFN1biwgRmViIDEyLCAyMDE3IGF0IDAyOjI4OjExUE0gKzAyMDAsIExhdXJlbnQgUGluY2hh cnQgd3JvdGU6Cj4gPj4gT24gVGh1cnNkYXkgMDIgRmViIDIwMTcgMTE6MzE6NTYgTWF4aW1lIFJp cGFyZCB3cm90ZToKPiA+PiA+IFRoaXMgcGF0Y2ggYWRkIGEgY29uZmlnIHRvIHN1cHBvcnQgdG8g Y3JlYXRlIG11bHRpIGJ1ZmZlciBmb3IgY21hIGZiZGV2Lgo+ID4+ID4gU3VjaCBhcyBkb3VibGUg YnVmZmVyIGFuZCB0cmlwbGUgYnVmZmVyLgo+ID4+ID4KPiA+PiA+IENtYSBmYmRldiBpcyBjb252 aWVudCB0byBhZGQgYSBsZWdlbmN5IGZiZGV2LiBBbmQgc3RpbGwgbWFueSBBbmRyb2lkCj4gPj4g PiBkZXZpY2VzIHVzZSBmYmRldiBub3cgYW5kIGF0IGxlYXN0IGRvdWJsZSBidWZmZXIgaXMgbmVl ZGVkIGZvciB0aGVzZQo+ID4+ID4gQW5kcm9pZCBkZXZpY2VzLCBzbyB0aGF0IGEgYnVmZmVyIGZs aXAgY2FuIGJlIG9wZXJhdGVkLiBJdCB3aWxsIG5lZWQKPiA+PiA+IHNvbWUgdGltZSBmb3IgQW5k cm9pZCBkZXZpY2UgdmVuZG9ycyB0byBhYm9uZG9uIGxlZ2VuY3kgZmJkZXYuIFNvIG11bHRpCj4g Pj4gPiBidWZmZXIgZm9yIGZiZGV2IGlzIG5lZWRlZC4KPiA+Pgo+ID4+IEhvdyBleGFjdGx5IGRv IHdlIGV4cGVjdCBBbmRyb2lkIHRvIG1vdmUgYXdheSBmcm9tIGZiZGV2IGlmIHdlIGFkZCBmZWF0 dXJlcyB0bwo+ID4+IHRoZSBmYmRldiBjb21wYXQgbGF5ZXIgPyBJJ2QgbXVjaCByYXRoZXIgbWFr ZSBpdCBjbGVhciB0byB0aGVtIHRoYXQgZmJkZXYgaXMgYQo+ID4+IHRoaW5nIGZyb20gdGhlIHBh c3QgYW5kIHRoYXQgdGhleSdkIGJldHRlciBtaWdyYXRlIG5vdy4KPiA+Cj4gPiBJZiB5b3VyIHBv aW50IGlzIHRoYXQgbWVyZ2luZyB0aGlzIHBhdGNoIHdpbGwgc2xvdyBkb3duIHRoZSBBbmRyb2lk Cj4gPiBtb3ZlIGF3YXkgZnJvbSBmYmRldiwgSSBkaXNhZ3JlZSB3aXRoIHRoYXQgKG9idmlvdXNs eSkuCj4gPgo+ID4gSSBkb24ndCBjYXJlIGF0IGFsbCBhYm91dCBBbmRyb2lkIG9uIG15IHBsYXRm b3JtIG9mIGNob2ljZSwgYnV0IGRvbid0Cj4gPiBzZWUgaG93IHRoYXQgbWVyZ2luZyB0aGlzIHBh dGNoIHdpbGwgY2hhbmdlIGFueXRoaW5nLgo+ID4KPiA+IExldCdzIGJlIGhvbmVzdCwgQW5kcm9p ZCB0cmVlcyB0eXBpY2FsbHkgaGF2ZSB0aG91c2FuZHMgb2YgcGF0Y2hlcyBvbgo+ID4gdG9wIG9m IG1haW5saW5lLiBEbyB5b3UgdGhpbmsgYSBzaW1wbGUsIDE1IExvQywgcGF0Y2ggd2lsbCBtYWtl IGFueQo+ID4gZGlmZmVyZW5jZSB0byB2ZW5kb3JzPyBJZiB0aGV5IHdhbnQgdG8gc3RheSBvbiBm YmRldiBhbmQgaGF2ZSB0aGF0Cj4gPiBmZWF0dXJlLCB0aGV5J2xsIGp1c3QgbWVyZ2UgdGhpcyBw YXRjaCwgZG9uZS4KPiAKPiBTbywgaW4gdGhhdCBjYXNlLCB3aHkgbm90IGp1c3QgbGV0IHRoZW0g ZG8gdGhhdD8gVGhleSdkIGFscmVhZHkgaGF2ZQo+IHRvIGFkZCBwYXRjaGVzIHRvIHVzZSB0aGlz LCBzdXJlbHk7IHdlIGRvbid0IGhhdmUgYW55dGhpbmcgaW4gbWFpbmxpbmUKPiBrZXJuZWxzIHdo aWNoIGFsbG93cyBwZW9wbGUgdG8gYWN0dWFsbHkgdXNlIHRoaXMgbGFyZ2VyIGFsbG9jYXRpb24u Cj4gQXBhcnQgZnJvbSBzb2Z0d2FyZSBtbWFwKCkgYW5kIHVzaW5nIHBhbm5pbmcgdG8gZG8gZmxp cHMsIGJ1dCBJJ20KPiB0YWtpbmcgaXQgYXMgYSBnaXZlbiB0aGF0IHBlb3BsZSBzaGlwcGluZyBB bmRyb2lkIG9uIHRoZWlyIGRldmljZXMKPiBhcmVuJ3QgdXNpbmcgc29mdHdhcmUgcmVuZGVyaW5n LgoKSSB0aGluayB3ZSBuZWVkIHRvIG1ha2UgYSBkaXN0aW5jdGlvbiBiZXR3ZWVuIGZiZGV2IHRo ZSBzdWJzeXN0ZW0gaW4gdGhlCmtlcm5lbCwgYW5kIGZiZGV2IHRoZSB1YWJpOgoKLSBmYmRldiB0 aGUgc3Vic3lzdGVtIGlzIGNvbXBsZXRlbHkgZGVhZCBpbiB1cHN0cmVhbS4gSSB0aGluayB3ZSBo YXZlIGZ1bGwKICBhZ3JlZW1lbnQgb24gdGhhdC4KLSBmYmRldiB0aGUgdWFiaSBpc24ndCwgYW5k IGlmIHdlIGNhbiBnZXQgbW9yZSB1c2VycyBmcm9tIGZiZGV2IGJhc2VkCiAgZHJpdmVycyB0byBr bXMvYXRvbWljIGRyaXZlcnMgYnkgYWRkaW5nIGZhaXJseSBzaW1wbGUgc3R1ZmYgbGlrZSB0aGlz LAogIEknbSBhbGwgZm9yIGl0LgoKV2hpY2ggbWVhbnM6IFllcywgSSBmdWxseSBwbGFuIHRvIG1l cmdlIHRoaXMsIGl0IG1ha2VzIHNlbnNlLiBJdCBldmVuCl9oZWxwc18gYnkgbWFraW5nIGZiZGV2 LXRoZS1zdWJzeXN0ZW0gZXZlbiBkZWFkZXIuIE1ha2luZyBsaXZlIGhhcmQgZm9yCm91dC1vZi10 cmVlIGZvbGtzIG9yIGZvbGtzIHdpdGggc2hpdCB1c2Vyc3BhY2UgZG9lc24ndCBtYWtlIHNlbnNl LCBhdApsZWFzdCBpZiB0aGUgb25seSBiZW5lZml0IGZvciB1cyBpcyB0aGF0IHdlJ2xsIGZlZWwg cHVyZSBhYm91dCBvdXIKaW50ZW50aW9ucyA6LSkKCkNoZWVycywgRGFuaWVsCi0tIApEYW5pZWwg VmV0dGVyClNvZnR3YXJlIEVuZ2luZWVyLCBJbnRlbCBDb3Jwb3JhdGlvbgpodHRwOi8vYmxvZy5m ZndsbC5jaApfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpk cmktZGV2ZWwgbWFpbGluZyBsaXN0CmRyaS1kZXZlbEBsaXN0cy5mcmVlZGVza3RvcC5vcmcKaHR0 cHM6Ly9saXN0cy5mcmVlZGVza3RvcC5vcmcvbWFpbG1hbi9saXN0aW5mby9kcmktZGV2ZWwK