From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751691AbbIQLwN (ORCPT ); Thu, 17 Sep 2015 07:52:13 -0400 Received: from mail-yk0-f179.google.com ([209.85.160.179]:35397 "EHLO mail-yk0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750792AbbIQLwL (ORCPT ); Thu, 17 Sep 2015 07:52:11 -0400 MIME-Version: 1.0 In-Reply-To: References: <1442309834-21420-1-git-send-email-kong.kongxinwei@hisilicon.com> <1442309834-21420-7-git-send-email-kong.kongxinwei@hisilicon.com> <55F862A1.30308@kernel.org> Date: Thu, 17 Sep 2015 07:52:10 -0400 Message-ID: Subject: Re: [PATCH RFC 6/8] drm: hisilicon: Add support for fbdev From: Rob Clark To: Xinliang Liu Cc: Rob Herring , linux-doc@vger.kernel.org, Catalin Marinas , Will Deacon , linuxarm@huawei.com, "dri-devel@lists.freedesktop.org" , Haojian Zhuang , Benjamin Gaignard , "Yanglong (James)" , Yinshengbao , xuyiping@hisilicon.com, Jonathan Corbet , Min Yi , xuwei5@hisilicon.com, Wang Fei , qijiwen@hisilicon.com, "devicetree@vger.kernel.org" , bintian.wang@huawei.com, puck.chen@hisilicon.com, Yanhaifeng , Dechun Fang , "linux-arm-kernel@lists.infradead.org" , Andy Green , gongyu@hisilicon.com, Linux Kernel Mailing List , Yangminglei , "Liguozhu (Kenneth)" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 16, 2015 at 5:48 AM, Xinliang Liu wrote: > > > On 16 September 2015 at 02:25, Rob Herring wrote: > Hi Rob, thanks a lot for reply:-) > >> On 09/15/2015 04:37 AM, Xinwei Kong wrote: >> > If you config DRM_HISI_FBDEV optional, this patch will only support >> > fbdev >> > mode while also supporting double buffer. >> >> This is a lot of duplicated code from CMA fbdev. Is double buffering the >> only reason why CMA fbdev can't be used or are there some other >> constraints? > > Yes, double buffering is the main reason we rewrite our own fbdev. > CMA fbdev only create one buffer. But we need at least double buffer for > running Android with fbdev. > >> Double buffering in fbdev has always been a hack, so I'm >> guessing that is not a feature that should be added here. >> > If so, I think it is hard to be accepted for my cma fbdev patch to support > multi buffer. > This early week, I have sent a cma fbdev patch for supporting this. The > subject is > "[PATCH] drm/cma-helper: Add multi buffer support for cma fbdev". > We do have a strong will to support this feature. I described the reason in > the patch. Please take a look for me. Thank you very much. fwiw, drm_gralloc has support for kms. Currently it is expected to be paired w/ a mesa gpu driver, which might not work for everyone, but I suppose the display part of it could be extracted out for a gralloc.kms.so for pure sw rendering.. that might be a better approach. http://git.android-x86.org/?p=platform/hardware/drm_gralloc.git BR, -R > -Xinliang > >> Rob >> >> > Signed-off-by: Xinliang Liu >> > Signed-off-by: Xinwei Kong >> > Signed-off-by: Andy Green >> > Signed-off-by: Jiwen Qi >> > Signed-off-by: Yu Gong >> > --- >> > drivers/gpu/drm/hisilicon/Kconfig | 13 + >> > drivers/gpu/drm/hisilicon/Makefile | 3 +- >> > drivers/gpu/drm/hisilicon/hisi_drm_connector.c | 4 + >> > drivers/gpu/drm/hisilicon/hisi_drm_drv.c | 9 + >> > drivers/gpu/drm/hisilicon/hisi_drm_dsi.c | 15 + >> > drivers/gpu/drm/hisilicon/hisi_drm_fb.h | 5 + >> > drivers/gpu/drm/hisilicon/hisi_drm_fbdev.c | 395 >> > +++++++++++++++++++++++++ >> > drivers/gpu/drm/hisilicon/hisi_drm_fbdev.h | 24 ++ >> > 8 files changed, 467 insertions(+), 1 deletion(-) >> > create mode 100644 drivers/gpu/drm/hisilicon/hisi_drm_fbdev.c >> > create mode 100644 drivers/gpu/drm/hisilicon/hisi_drm_fbdev.h >> > > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/dri-devel >