Re: [PATCH v7 3/7] drm/display: Add soft depend for aux-hpd-typec-dp-bridge module

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Dependency inversion unconditionally loads USB Type-C subsystem on all DP-capable systems
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commit 18e75df5599eb3c3479dc1002547dcf5f6a1593b
Author: Chaoyi Chen <chaoyi.chen@rock-chips.com>

drm/display: Add soft depend for aux-hpd-typec-dp-bridge module

This commit adds a soft dependency in the drm_display_helper module for the
aux-hpd-typec-dp-bridge module. This ensures the bridge module is loaded
early, as it serves as a generic Type-C DisplayPort HPD bridge that isn't
directly required by any other module.

> diff --git a/drivers/gpu/drm/display/drm_display_helper_mod.c b/drivers/gpu/drm/display/drm_display_helper_mod.c
> index d8a6e62287736..f0152d6b0b2d7 100644
> --- a/drivers/gpu/drm/display/drm_display_helper_mod.c
> +++ b/drivers/gpu/drm/display/drm_display_helper_mod.c
> @@ -18,5 +18,6 @@ static void __exit drm_display_helper_module_exit(void)
>  	drm_dp_aux_dev_exit();
>  }
>  
> +MODULE_SOFTDEP("pre: aux-hpd-typec-dp-bridge");

[Severity: Medium]
Does adding a soft dependency on aux-hpd-typec-dp-bridge to the core
drm_display_helper module create an architectural dependency inversion?

The leaf bridge driver (aux-hpd-typec-dp-bridge) has a hard dependency on the
typec core subsystem because it registers a bus notifier on typec_bus. As a
result, when a system loads a DRM driver that utilizes generic display helpers
(such as amdgpu, i915, or nouveau), won't this unconditionally pull the entire
USB Type-C subsystem into memory?

This seems like it might waste memory resources on systems without Type-C
hardware by automatically loading aux-hpd-typec-dp-bridge.ko (and consequently
typec.ko) upon loading any standard DRM driver. Is there a better way to
handle this without burdening all generic display helper users?

>  module_init(drm_display_helper_module_init);
>  module_exit(drm_display_helper_module_exit);

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260828084737.565-1-kernel@airkyi.com?part=3

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