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

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Message-ID: <7cb50c9c-ac41-43b6-8c69-5f184e7c94cf@samsung.com>
Date: Thu, 14 Aug 2025 23:16:59 +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 16:33, Marek Szyprowski wrote:
> 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.

The failure is caused by trying to add plat_data->next_bridge twice 
(from exynos_dp's .attach callback, and from analogix' ->bind callback).


Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland