From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xinliang Liu Subject: Re: [PATCH RFC 6/8] drm: hisilicon: Add support for fbdev Date: Wed, 16 Sep 2015 17:48:56 +0800 Message-ID: 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> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0208114624==" Return-path: In-Reply-To: <55F862A1.30308@kernel.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Rob Herring Cc: linux-doc@vger.kernel.org, catalin.marinas@arm.com, will.deacon@arm.com, linuxarm@huawei.com, dri-devel@lists.freedesktop.org, Haojian Zhuang , Benjamin Gaignard , "Yanglong (James)" , Yinshengbao , xuyiping@hisilicon.com, corbet@lwn.net, 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@vger.kernel.org, Yangminglei , "Liguozhu (Kenneth)" List-Id: devicetree@vger.kernel.org --===============0208114624== Content-Type: multipart/alternative; boundary=001a113cc51608a83a051fda354b --001a113cc51608a83a051fda354b Content-Type: text/plain; charset=UTF-8 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. -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 > > --001a113cc51608a83a051fda354b Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On 16 September 2015 at 02:25, Rob Herring <robh@kernel.org> wrote:
Hi Rob, thanks a lot for reply:-)=

On 09/15/2015 0= 4:37 AM, Xinwei Kong wrote:
> If you config DRM_HISI_FBDEV optional, this patch will only support fb= dev
> 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 n= eed at least =C2=A0double 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 buf= fer.
This early week, I have sent a cma fbdev patch for supportin= g this. The subject is=C2=A0
"[PATCH] drm/cma-helper: Add mu= lti 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.

-Xinliang
=

Rob

> Signed-off-by: Xinliang Liu <xinliang.liu@linaro.org>
> Signed-off-by: Xinwei Kong <kong.kongxinwei@hisilicon.com>
> Signed-off-by: Andy Green <andy.green@linaro.org>
> Signed-off-by: Jiwen Qi <qijiwen@hisilicon.com>
> Signed-off-by: Yu Gong <gongyu@hisilicon.com>
> ---
>=C2=A0 drivers/gpu/drm/hisilicon/Kconfig=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 |=C2=A0 13 +
>=C2=A0 drivers/gpu/drm/hisilicon/Makefile=C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0|=C2=A0 =C2=A03 +-
>=C2=A0 drivers/gpu/drm/hisilicon/hisi_drm_connector.c |=C2=A0 =C2=A04 +=
>=C2=A0 drivers/gpu/drm/hisilicon/hisi_drm_drv.c=C2=A0 =C2=A0 =C2=A0 =C2= =A0|=C2=A0 =C2=A09 +
>=C2=A0 drivers/gpu/drm/hisilicon/hisi_drm_dsi.c=C2=A0 =C2=A0 =C2=A0 =C2= =A0|=C2=A0 15 +
>=C2=A0 drivers/gpu/drm/hisilicon/hisi_drm_fb.h=C2=A0 =C2=A0 =C2=A0 =C2= =A0 |=C2=A0 =C2=A05 +
>=C2=A0 drivers/gpu/drm/hisilicon/hisi_drm_fbdev.c=C2=A0 =C2=A0 =C2=A0| = 395 +++++++++++++++++++++++++
>=C2=A0 drivers/gpu/drm/hisilicon/hisi_drm_fbdev.h=C2=A0 =C2=A0 =C2=A0|= =C2=A0 24 ++
>=C2=A0 8 files changed, 467 insertions(+), 1 deletion(-)
>=C2=A0 create mode 100644 drivers/gpu/drm/hisilicon/hisi_drm_fbdev.c >=C2=A0 create mode 100644 drivers/gpu/drm/hisilicon/hisi_drm_fbdev.h

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