linux-kernel - Re: [v14, 01/17] drm: bridge: analogix/dp: split exynos dp driver to bridge directory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20160331095600.GD26032@ulmo.nvidia.com>
Date:	Thu, 31 Mar 2016 11:56:02 +0200
From:	Thierry Reding <treding@...dia.com>
To:	Guenter Roeck <linux@...ck-us.net>
CC:	Yakir Yang <ykk@...k-chips.com>, Inki Dae <inki.dae@...sung.com>,
	"Andrzej Hajda" <a.hajda@...sung.com>,
	Joonyoung Shim <jy0922.shim@...sung.com>,
	Seung-Woo Kim <sw0312.kim@...sung.com>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Jingoo Han <jingoohan1@...il.com>,
	"Krzysztof Kozlowski" <k.kozlowski@...sung.com>,
	Rob Herring <robh+dt@...nel.org>,
	"Heiko Stuebner" <heiko@...ech.de>,
	Mark Yao <mark.yao@...k-chips.com>,
	Russell King <linux@....linux.org.uk>, <djkurtz@...omium.org>,
	Sean Paul <seanpaul@...omium.org>,
	Kukjin Kim <kgene@...nel.org>,
	Kumar Gala <galak@...eaurora.org>, <emil.l.velikov@...il.com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Gustavo Padovan <gustavo.padovan@...labora.co.uk>,
	Kishon Vijay Abraham I <kishon@...com>,
	Pawel Moll <pawel.moll@....com>, <ajaynumb@...il.com>,
	<robherring2@...il.com>, <javier@....samsung.com>,
	Andy Yan <andy.yan@...k-chips.com>,
	<dri-devel@...ts.freedesktop.org>, <devicetree@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>,
	<linux-samsung-soc@...r.kernel.org>,
	<linux-rockchip@...ts.infradead.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	Douglas Anderson <dianders@...omium.org>
Subject: Re: [v14, 01/17] drm: bridge: analogix/dp: split exynos dp driver to
 bridge directory

On Wed, Mar 30, 2016 at 01:32:04PM -0700, Guenter Roeck wrote:
> Hi,
> 
> On Mon, Feb 15, 2016 at 07:09:36PM +0800, Yakir Yang wrote:
> > Split the dp core driver from exynos directory to bridge directory,
> > and rename the core driver to analogix_dp_*, rename the platform
> > code to exynos_dp.
> > 
> > Beside the new analogix_dp driver would export six hooks.
> > "analogix_dp_bind()" and "analogix_dp_unbind()"
> > "analogix_dp_suspned()" and "analogix_dp_resume()"
> > "analogix_dp_detect()" and "analogix_dp_get_modes()"
> > 
> > The bind/unbind symbols is used for analogix platform driver to connect
> > with analogix_dp core driver. And the detect/get_modes is used for analogix
> > platform driver to init the connector.
> > 
> > They reason why connector need register in helper driver is rockchip drm
> > haven't implement the atomic API, but Exynos drm have implement it, so
> > there would need two different connector helper functions, that's why we
> > leave the connector register in helper driver.
> > 
> > Signed-off-by: Yakir Yang <ykk@...k-chips.com>
> > 
> [ ... ]
> 
> > diff --git a/drivers/gpu/drm/bridge/analogix/Makefile b/drivers/gpu/drm/bridge/analogix/Makefile
> > new file mode 100644
> > index 0000000..9107b86
> > --- /dev/null
> > +++ b/drivers/gpu/drm/bridge/analogix/Makefile
> > @@ -0,0 +1 @@
> > +obj-$(CONFIG_DRM_ANALOGIX_DP) += analogix_dp_core.o analogix_dp_reg.o
> 
> This results in the following build errors if DRM_ANALOGIX_DP
> is configured as module.
> 
> ERROR: "analogix_dp_start_video" [drivers/gpu/drm/bridge/analogix/analogix_dp_core.ko] undefined!
> ERROR: "analogix_dp_get_lane0_link_training" [drivers/gpu/drm/bridge/analogix/analogix_dp_core.ko] undefined!
> ERROR: "analogix_dp_get_lane1_link_training" [drivers/gpu/drm/bridge/analogix/analogix_dp_core.ko] undefined!
> ERROR: "analogix_dp_get_lane2_link_training" [drivers/gpu/drm/bridge/analogix/analogix_dp_core.ko] undefined!
> ERROR: "analogix_dp_get_lane3_link_training" [drivers/gpu/drm/bridge/analogix/analogix_dp_core.ko] undefined!
> ERROR: "analogix_dp_get_lane_count" [drivers/gpu/drm/bridge/analogix/analogix_dp_core.ko] undefined!
> ERROR: "analogix_dp_get_link_bandwidth" [drivers/gpu/drm/bridge/analogix/analogix_dp_core.ko] undefined!
> 
> [ and so on ]

Ugh... most of these functions shouldn't be there in the first place. We
have helpers in the core that already do this. Most of the functionality
is duplicated in this driver.

I realize that this is a problem that existed in the Exynos DP driver,
but somebody really ought to rewrite those parts to make use of the DRM
DP helpers.

Thierry

Download attachment "signature.asc" of type "application/pgp-signature" (820 bytes)