linux-kernel - Re: [PATCH v7 2/9] drm/bridge: Implement generic USB Type-C DP HPD bridge

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: <aPnrKFWTvpuRTyhI@kuha.fi.intel.com>
Date: Thu, 23 Oct 2025 11:45:28 +0300
From: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To: Chaoyi Chen <kernel@...kyi.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, Vinod Koul <vkoul@...nel.org>,
	Kishon Vijay Abraham I <kishon@...nel.org>,
	Heiko Stuebner <heiko@...ech.de>, Sandy Huang <hjc@...k-chips.com>,
	Andy Yan <andy.yan@...k-chips.com>,
	Yubing Zhang <yubing.zhang@...k-chips.com>,
	Frank Wang <frank.wang@...k-chips.com>,
	Andrzej Hajda <andrzej.hajda@...el.com>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Robert Foss <rfoss@...nel.org>,
	Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
	Jonas Karlman <jonas@...boo.se>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
	Amit Sunil Dhamne <amitsd@...gle.com>,
	Chaoyi Chen <chaoyi.chen@...k-chips.com>,
	Dragan Simic <dsimic@...jaro.org>, Johan Jonker <jbx6244@...il.com>,
	Diederik de Haas <didi.debian@...ow.org>,
	Peter Robinson <pbrobinson@...il.com>, linux-usb@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-phy@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org,
	linux-rockchip@...ts.infradead.org, dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH v7 2/9] drm/bridge: Implement generic USB Type-C DP HPD
 bridge

On Thu, Oct 23, 2025 at 11:30:02AM +0800, Chaoyi Chen wrote:
> From: Chaoyi Chen <chaoyi.chen@...k-chips.com>
> 
> Several USB-C controller drivers have already implemented the DP HPD
> bridge function provided by aux-hpd-bridge.c, but there are still
> some USB-C controller driver that have not yet implemented it.
> 
> This patch implements a generic DP HPD bridge based on aux-hpd-bridge.c,
> so that other USB-C controller drivers don't need to implement it again.
> 
> Signed-off-by: Chaoyi Chen <chaoyi.chen@...k-chips.com>
> ---
>  drivers/gpu/drm/bridge/Kconfig                | 11 ++++
>  drivers/gpu/drm/bridge/Makefile               |  1 +
>  .../gpu/drm/bridge/aux-hpd-typec-dp-bridge.c  | 51 +++++++++++++++++++
>  3 files changed, 63 insertions(+)
>  create mode 100644 drivers/gpu/drm/bridge/aux-hpd-typec-dp-bridge.c
> 
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index b9e0ca85226a..9f31540d3ad8 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -33,6 +33,17 @@ config DRM_AUX_HPD_BRIDGE
>  menu "Display Interface Bridges"
>  	depends on DRM && DRM_BRIDGE
>  
> +config DRM_AUX_TYPEC_DP_HPD_BRIDGE
> +	tristate "TypeC DP HPD bridge"
> +	depends on DRM_BRIDGE && OF && TYPEC
> +	select DRM_AUX_HPD_BRIDGE
> +	help
> +	  Simple USB Type-C DP bridge that terminates the bridge chain and
> +	  provides HPD support.
> +
> +	  If the USB-C controller driver has not implemented this and you need
> +	  the DP HPD support, say "Y" or "m" here.

You don't need to depend on DRM_BRIDGE separately, but do you really
need a separate module for this in the first place?

>  config DRM_CHIPONE_ICN6211
>  	tristate "Chipone ICN6211 MIPI-DSI/RGB Converter bridge"
>  	depends on OF
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index 245e8a27e3fc..e91736829167 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -1,6 +1,7 @@
>  # SPDX-License-Identifier: GPL-2.0
>  obj-$(CONFIG_DRM_AUX_BRIDGE) += aux-bridge.o
>  obj-$(CONFIG_DRM_AUX_HPD_BRIDGE) += aux-hpd-bridge.o
> +obj-$(CONFIG_DRM_AUX_TYPEC_DP_HPD_BRIDGE) += aux-hpd-typec-dp-bridge.o

Instead, why not just make that a part of aux-hpd-bridge
conditionally:

ifneq ($(CONFIG_TYPEC),)
        aux-hpd-bridge-y        += aux-hpd-typec-dp-bridge.o
endif


thanks,

-- 
heikki