Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753968AbcD2PiR (ORCPT ); Fri, 29 Apr 2016 11:38:17 -0400 Received: from mail-oi0-f47.google.com ([209.85.218.47]:35797 "EHLO mail-oi0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753910AbcD2PiO (ORCPT ); Fri, 29 Apr 2016 11:38:14 -0400 MIME-Version: 1.0 X-Originating-IP: [2a02:168:56b5:0:ac27:b86c:7764:9429] In-Reply-To: <20160429153636.GE14148@phenom.ffwll.local> References: <1461856717-6476-1-git-send-email-noralf@tronnes.org> <1461856717-6476-4-git-send-email-noralf@tronnes.org> <572358A0.8010002@ti.com> <20160429145524.GC14148@phenom.ffwll.local> <57237702.8060305@ti.com> <20160429153636.GE14148@phenom.ffwll.local> Date: Fri, 29 Apr 2016 17:38:08 +0200 X-Google-Sender-Auth: vpf6PoUCT3w_G3y14sW7BoEwYNU Message-ID: Subject: Re: [PATCH v4 3/7] drm/fb-helper: Add fb_deferred_io support From: Daniel Vetter To: Tomi Valkeinen , =?UTF-8?Q?Noralf_Tr=C3=B8nnes?= , dri-devel , Linux Fbdev development list , Laurent Pinchart , Linux Kernel Mailing List , David Herrmann Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2192 Lines: 54 Adding David, forgot that before hitting send. -Daniel On Fri, Apr 29, 2016 at 5:36 PM, Daniel Vetter wrote: > On Fri, Apr 29, 2016 at 06:00:18PM +0300, Tomi Valkeinen wrote: >> >> On 29/04/16 17:55, Daniel Vetter wrote: >> >> >> Who's calling {write,fillrect,copyarea,imageblit} in an atomic context? >> >> That sounds like a very bad idea to me... >> >> >> >> If this is only for accumulating changes, I think it may be better to >> >> leave that to the driver as it may have better idea of how to accumulate. >> >> >> >> But, of course, this is a helper, so if all the drivers use this kind of >> >> accumulation, it makes sense =). >> > >> > Apparently panic context and cursor timer and stuff like that. I think >> > this started with udl, and just to make sure (it's fbdev after all, no one >> > wants to read the code itself) we've put those checks onto all entry >> > points that draw stuff. It could be overkill, but this is what udl/qxl >> > already do, so better to keep imo for now. >> > >> > I guess if it's really not needed we could later on change that, but not >> > sure that's worth the effort. And we can't get rid of it entirely. >> >> Yep... Sounds fine to me. >> >> Someone should implement (minimal) fbdev userspace API support to DRM >> without using the current fbdev, and implement fbcon on top of that. I >> don't like how DRM and fbdev gets mixed... >> >> I offer a beer to anyone who does that =). > > The big plan that has been floated years back already (before David > Herrmann disappeared into the rh systemd gang) was to have a pure > userspace kmscon for console (including vt-switching in userspace like X > does), plus a super-minimal panic console on top of kms in the kernel. > That looked like a really solid design, unfornutately it didn't go > anywhere. But basic patches are still around, and it really just boils > down to that some distro would need to integrate kmscon properly, and > polish of the kernel side too for integration. > -Daniel > -- > Daniel Vetter > Software Engineer, Intel Corporation > http://blog.ffwll.ch -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch