From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751970AbbCJJw7 (ORCPT ); Tue, 10 Mar 2015 05:52:59 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:60042 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751716AbbCJJw5 (ORCPT ); Tue, 10 Mar 2015 05:52:57 -0400 Message-ID: <54FEBEF1.5000103@codeaurora.org> Date: Tue, 10 Mar 2015 15:22:49 +0530 From: Archit Taneja User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: robdclark@gmail.com, airlied@linux.ie, treding@nvidia.com, p.zabel@pengutronix.de, benjamin.gaignard@linaro.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, daniel@ffwll.ch, daniel.vetter@ffwll.ch Subject: Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation References: <1425980493-27533-1-git-send-email-architt@codeaurora.org> <1425980493-27533-2-git-send-email-architt@codeaurora.org> <20150310094756.GE3800@phenom.ffwll.local> In-Reply-To: <20150310094756.GE3800@phenom.ffwll.local> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/10/2015 03:17 PM, Daniel Vetter wrote: > On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote: >> Legacy fbdev emulation support via DRM is achieved through KMS FB helpers. >> Most modesetting drivers enable provide fbdev emulation by default by selecting >> KMS FB helpers. A few provide a separate Kconfig option for the user to enable >> or disbale fbdev emulation. >> >> Enabling fbdev emulation is finally a distro-level decision. Having a top level >> Kconfig option for fbdev emulation helps by providing a uniform way to >> enable/disable fbdev emulation for any modesetting driver. It also lets us >> remove unnecessary driver specific Kconfig options that causes bloat. >> >> With a top level Kconfig in place, we can stub out the fb helper functions when >> not needed without breaking functionality. Having stub functions also prevents >> drivers to require wrapping fb helper function calls with #ifdefs. >> >> DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by >> default and majority of distributions expect the fbdev interface in the kernel. >> >> For now, this config selects both FB_SYS_* and FB_CFB_* configs as some >> modesetting drivers use the former and other the later. This needs to be taken >> care of in a better way. >> >> Signed-off-by: Archit Taneja >> --- >> drivers/gpu/drm/Kconfig | 18 +++++++ >> drivers/gpu/drm/Makefile | 4 ++ >> include/drm/drm_fb_helper.h | 120 ++++++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 142 insertions(+) >> >> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig >> index 151a050..38f83a0 100644 >> --- a/drivers/gpu/drm/Kconfig >> +++ b/drivers/gpu/drm/Kconfig >> @@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER >> help >> FBDEV helpers for KMS drivers. >> >> +config DRM_FBDEV_EMULATION >> + bool "Enable legacy fbdev support for your modesetting driver" >> + depends on DRM >> + select DRM_KMS_HELPER >> + select DRM_KMS_FB_HELPER >> + select FB_SYS_FILLRECT >> + select FB_SYS_COPYAREA >> + select FB_SYS_IMAGEBLIT >> + select FB_SYS_FOPS >> + select FB_CFB_FILLRECT >> + select FB_CFB_COPYAREA >> + select FB_CFB_IMAGEBLIT >> + default y >> + help >> + Choose this option if you have a need for the legacy fbdev >> + support. Note that this support also provide the linux console >> + support on top of your modesetting driver. > > Maybe clarify that for linux console support you also need > CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough. DRM_KMS_FB_HELPER selects that for us, right? Archit