Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932182AbcLHKKC (ORCPT ); Thu, 8 Dec 2016 05:10:02 -0500 Received: from mail-wm0-f65.google.com ([74.125.82.65]:32959 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932105AbcLHKJ7 (ORCPT ); Thu, 8 Dec 2016 05:09:59 -0500 Date: Thu, 8 Dec 2016 11:10:05 +0100 From: Daniel Vetter To: Benjamin Herrenschmidt Cc: Tomi Valkeinen , linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, Greg Kroah-Hartman , Thomas Petazzoni , Noralf =?iso-8859-1?Q?Tr=F8nnes?= , Sudip Mukherjee , Teddy Wang , Arnaud Patard , linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 0/3] staging: remove fbdev drivers Message-ID: <20161208101005.6ufl3d4qvwprosju@phenom.ffwll.local> Mail-Followup-To: Benjamin Herrenschmidt , Tomi Valkeinen , linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, Greg Kroah-Hartman , Thomas Petazzoni , Noralf =?iso-8859-1?Q?Tr=F8nnes?= , Sudip Mukherjee , Teddy Wang , Arnaud Patard , linux-kernel@vger.kernel.org References: <1479888193-23908-1-git-send-email-tomi.valkeinen@ti.com> <1481158879.26959.41.camel@kernel.crashing.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1481158879.26959.41.camel@kernel.crashing.org> X-Operating-System: Linux phenom 4.8.0-1-amd64 User-Agent: NeoMutt/20161104 (1.7.1) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1898 Lines: 46 On Thu, Dec 08, 2016 at 12:01:19PM +1100, Benjamin Herrenschmidt wrote: > On Wed, 2016-11-23 at 10:03 +0200, Tomi Valkeinen wrote: > > Hi, > > > > Since the fbdev framework is in maintenance mode and all new display drivers > > should be made with the DRM framework, remove the fbdev drivers from staging. > > > > Note: the patches are created with git format-patch -D, so they can't be > > applied. Only for review. > > I missed the discussion where this decision was made, I admit I am > unimpressed by it. > > DRM drivers don't strike me as suitable for small/slow cores with dumb > framebuffers or simple 2D only accel, such as the one found in the ASpeed > BMCs. We have a helper for simple drivers now, if you take into account the massive helper libraries for everything that comes along with drm I expect if even dumb panels behind slow spi buses drm is now the more suitable subsytem. > With drmfb you basically have to shadow everything into memory & copy > over everything, and locks you out of simple 2D accel. For a simple text > console the result is orders of magnitude slower and memory hungry than > a simple fbdev. Not true, we have full fbdev emulation, and drivers can implement the 2d accel in there. And a bunch of them do. It's just that most teams decided that this is pointless waste of their time.j > At least that was the case last I looked at the DRM stuff with Dave, > maybe things have changed... > > Not everything has a powerful 3D GPU. That's correct, and drm can cope. And compared to fbdev there's a very active community who improves&refactors it every kernel release to make it even better. Since about 2 years (when atomic landed) we merge new drivers at a rate of 2-3 per kernel release, and those new drivers get ever simpler and smaller thanks to all this work. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch