linux-kernel - Re: [PATCH v4 00/13] Apply drm_bridge_connector and panel

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Message-ID: <a3a2f8be-2c3c-49e7-b27a-72364ea48b06@samsung.com>
Date: Thu, 14 Aug 2025 16:33:36 +0200
From: Marek Szyprowski <m.szyprowski@...sung.com>
To: Damon Ding <damon.ding@...k-chips.com>, andrzej.hajda@...el.com,
	neil.armstrong@...aro.org, rfoss@...nel.org
Cc: Laurent.pinchart@...asonboard.com, jonas@...boo.se,
	jernej.skrabec@...il.com, maarten.lankhorst@...ux.intel.com,
	mripard@...nel.org, tzimmermann@...e.de, airlied@...il.com, simona@...ll.ch,
	jingoohan1@...il.com, inki.dae@...sung.com, sw0312.kim@...sung.com,
	kyungmin.park@...sung.com, krzk@...nel.org, alim.akhtar@...sung.com,
	hjc@...k-chips.com, heiko@...ech.de, andy.yan@...k-chips.com,
	dmitry.baryshkov@....qualcomm.com, l.stach@...gutronix.de,
	dianders@...omium.org, dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-samsung-soc@...r.kernel.org, linux-rockchip@...ts.infradead.org
Subject: Re: [PATCH v4 00/13] Apply drm_bridge_connector and panel_bridge
 helper for the Analogix DP driver

On 14.08.2025 12:47, Damon Ding wrote:
> PATCH 1 is a small format optimization for struct analogid_dp_device.
> PATCH 2 is to perform mode setting in &drm_bridge_funcs.atomic_enable.
> PATCH 3-6 are preparations for apply drm_bridge_connector helper.
> PATCH 7 is to apply the drm_bridge_connector helper.
> PATCH 8-10 are to move the panel/bridge parsing to the Analogix side.
> PATCH 11-12 are preparations for apply panel_bridge helper.
> PATCH 13 is to apply the panel_bridge helper.

This series lacks 'select DRM_BRIDGE_CONNECTOR' in ExynosDP's Kconfig, 
so it causes build break:

drivers/gpu/drm/exynos/exynos_dp.c:177: undefined reference to 
`drm_bridge_connector_init'
make[2]: *** [scripts/Makefile.vmlinux:91: vmlinux] Error 1

After adding this dependency, the Exynos DP driver stops working. On 
Samsung Snow Chromebook I observed following issue:

[    4.534220] exynos-dp 145b0000.dp-controller: failed to attach 
following panel or bridge (-16)
[    4.543428] exynos-drm exynos-drm: failed to bind 
145b0000.dp-controller (ops exynos_dp_ops): -16
[    4.551775] exynos-drm exynos-drm: adev bind failed: -16
[    4.556559] exynos-dp 145b0000.dp-controller: probe with driver 
exynos-dp failed with error -16

I will investigate details later in the evening.

> Damon Ding (13):
>    drm/bridge: analogix_dp: Formalize the struct analogix_dp_device
>    drm/bridge: analogix_dp: Move &drm_bridge_funcs.mode_set to
>      &drm_bridge_funcs.atomic_enable
>    drm/bridge: analogix_dp: Add &analogix_dp_plat_data.next_bridge
>    drm/exynos: exynos_dp: Remove &exynos_dp_device.ptn_bridge
>    drm/bridge: exynos_dp: Remove unused &exynos_dp_device.connector
>    drm/bridge: analogix_dp: Remove redundant
>      &analogix_dp_plat_data.skip_connector
>    drm/bridge: analogix_dp: Apply drm_bridge_connector helper
>    drm/bridge: analogix_dp: Add new API analogix_dp_finish_probe()
>    drm/rockchip: analogix_dp: Apply analogix_dp_finish_probe()
>    drm/exynos: exynos_dp: Apply analogix_dp_finish_probe()
>    drm/bridge: analogix_dp: Remove panel disabling and enabling in
>      analogix_dp_set_bridge()
>    drm/bridge: analogix_dp: Remove bridge disabing and panel unpreparing
>      in analogix_dp_unbind()
>    drm/bridge: analogix_dp: Apply panel_bridge helper
>
>   .../drm/bridge/analogix/analogix_dp_core.c    | 384 ++++++++++--------
>   .../drm/bridge/analogix/analogix_dp_core.h    |   5 +-
>   drivers/gpu/drm/exynos/exynos_dp.c            |  48 +--
>   .../gpu/drm/rockchip/analogix_dp-rockchip.c   |  49 +--
>   include/drm/bridge/analogix_dp.h              |   7 +-
>   5 files changed, 248 insertions(+), 245 deletions(-)
>
> ---
>
> Changes in v2:
> - Update Exynos DP driver synchronously.
> - Move the panel/bridge parsing to the Analogix side.
>
> Changes in v3:
> - Rebase for the existing devm_drm_bridge_alloc() applying commit.
> - Fix the typographical error of panel/bridge check in exynos_dp_bind().
> - Squash all commits related to skip_connector deletion in both Exynos and
>    Analogix code into one.
> - Apply panel_bridge helper to make the codes more concise.
> - Fix the handing of bridge in analogix_dp_bridge_get_modes().
> - Remove unnecessary parameter struct drm_connector* for callback
>    &analogix_dp_plat_data.attach().
> - In order to decouple the connector driver and the bridge driver, move
>    the bridge connector initilization to the Rockchip and Exynos sides.
>
> Changes in v4:
> - Rebase for the applied &drm_bridge_funcs.detect() modification commit.
> - Rename analogix_dp_find_panel_or_bridge() to analogix_dp_finish_probe().
> - Drop the drmm_encoder_init() modification commit.
> - Rename the &analogix_dp_plat_data.bridge to
>    &analogix_dp_plat_data.next_bridge.
>
Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland