From: Luca Ceresoli <luca.ceresoli@bootlin•com>
To: Maarten Lankhorst <maarten.lankhorst@linux•intel.com>,
Maxime Ripard <mripard@kernel•org>,
Thomas Zimmermann <tzimmermann@suse•de>,
David Airlie <airlied@gmail•com>,
Simona Vetter <simona@ffwll•ch>,
Andrzej Hajda <andrzej.hajda@intel•com>,
Neil Armstrong <neil.armstrong@linaro•org>,
Robert Foss <rfoss@kernel•org>,
Laurent Pinchart <Laurent.pinchart@ideasonboard•com>,
Jonas Karlman <jonas@kwiboo•se>,
Jernej Skrabec <jernej.skrabec@gmail•com>,
Inki Dae <inki.dae@samsung•com>,
Jagan Teki <jagan@amarulasolutions•com>,
Marek Szyprowski <m.szyprowski@samsung•com>,
Marek Vasut <marex@denx•de>, Stefan Agner <stefan@agner•ch>,
Frank Li <Frank.Li@nxp•com>,
Sascha Hauer <s.hauer@pengutronix•de>,
Pengutronix Kernel Team <kernel@pengutronix•de>,
Fabio Estevam <festevam@gmail•com>
Cc: Hui Pu <Hui.Pu@gehealthcare•com>,
Ian Ray <ian.ray@gehealthcare•com>,
Thomas Petazzoni <thomas.petazzoni@bootlin•com>,
dri-devel@lists•freedesktop.org, linux-kernel@vger•kernel.org,
imx@lists•linux.dev, linux-arm-kernel@lists•infradead.org,
Luca Ceresoli <luca.ceresoli@bootlin•com>
Subject: [PATCH 18/37] drm/bridge: samsung-dsim: remove the panel_bridge on host_detach
Date: Tue, 19 May 2026 12:37:35 +0200 [thread overview]
Message-ID: <20260519-drm-bridge-hotplug-v1-18-45e2bdb3dfb4@bootlin.com> (raw)
In-Reply-To: <20260519-drm-bridge-hotplug-v1-0-45e2bdb3dfb4@bootlin.com>
In preparation for DRM bridge hot-plugging, we need to handle the dynamic
lifetime of the following bridge in case the samsung-dsim is always present
and the following bridge (next_bridge) is hot-unplugged.
Based on the 'if (!IS_ERR(panel))' check in samsung_dsim_host_attach(), the
next_bridge could be A) a panel bridge created by this driver via
devm_drm_panel_bridge_add() or B) a pre-existing bridge obtained via
of_drm_find_and_get_bridge().
For case B) we need to put that reference when the next_bridge is removed,
which is already handled by calling drm_bridge_clear_and_put() in
samsung_dsim_host_detach() and in the samsung_dsim_host_attach() error
management code.
In case A) we additionally have to remove the panel bridge. Currently it is
created by devm_drm_panel_bridge_add(), which adds two devm actions with
the refcounted panel bridge:
- drm_bridge_put_void() via devm_drm_bridge_alloc() on panel->dev
- devm_drm_panel_bridge_release() via devm_drm_panel_bridge_add_typed()
on the consumer device (samsung-dsim)
The first action is OK: being tied to panel->dev it will happen when the
panel is unplugged.
The second action is bound to the consumer device, so the devm semantics is
not useful here when introducing hotplug. Indeed we need to drop the
next_bridge in samsung_dsim_host_detach() anyway, before the driver .remove
function, in order to support {add, {attach, detach} x N, remove} hotplug
event sequences.
Thus move to the non-devm drm_panel_bridge_add() along with the matching
drm_panel_bridge_remove(), so the lifetime of the panel-bridge is tied to
the host_attach/host_detach cycle and not the whole samsung-dsim device
lifetime.
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin•com>
---
In a previous discussion with Maxime he mentioned a plan to make every
drm_panel always have a wrapping bridge. With that done, all the code
handling the panel and adding the panel_bridge would become useless here
(and in many other places) and could be entirely removed. This patch is a
temporary solution until that happens. The best pointer I could find to
that discussion is [0], but there might be more recent material I could not
find at the moment.
[0] https://lore.kernel.org/lkml/20250218-faithful-white-magpie-da9ac9@houat/
---
drivers/gpu/drm/bridge/samsung-dsim.c | 17 ++++++++++++++---
include/drm/bridge/samsung-dsim.h | 2 ++
2 files changed, 16 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
index 5b799619e07e..2af287221e22 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -1951,14 +1951,16 @@ static int samsung_dsim_host_attach(struct mipi_dsi_host *host,
if (!remote)
return -ENODEV;
+ dsi->panel_bridge_added = false;
panel = of_drm_find_panel(remote);
if (!IS_ERR(panel)) {
- next_bridge = devm_drm_panel_bridge_add(dev, panel);
+ next_bridge = drm_panel_bridge_add(panel);
if (IS_ERR(next_bridge)) {
ret = PTR_ERR(next_bridge);
next_bridge = NULL; // Inhibit the cleanup action on an ERR_PTR
} else {
drm_bridge_get(next_bridge);
+ dsi->panel_bridge_added = true;
}
} else {
next_bridge = of_drm_find_and_get_bridge(remote);
@@ -1989,7 +1991,7 @@ static int samsung_dsim_host_attach(struct mipi_dsi_host *host,
if (!(device->mode_flags & MIPI_DSI_MODE_VIDEO)) {
ret = samsung_dsim_register_te_irq(dsi, &device->dev);
if (ret)
- goto err_remove_bridge;
+ goto err_remove_panel_bridge;
}
// The next bridge can be used by host_ops->attach
@@ -2011,8 +2013,12 @@ static int samsung_dsim_host_attach(struct mipi_dsi_host *host,
drm_bridge_clear_and_put(&dsi->bridge.next_bridge);
if (!(device->mode_flags & MIPI_DSI_MODE_VIDEO))
samsung_dsim_unregister_te_irq(dsi);
-err_remove_bridge:
+err_remove_panel_bridge:
drm_bridge_remove(&dsi->bridge);
+ if (dsi->panel_bridge_added) {
+ drm_panel_bridge_remove(next_bridge);
+ dsi->panel_bridge_added = false;
+ }
return ret;
}
@@ -2022,6 +2028,11 @@ static int samsung_dsim_host_detach(struct mipi_dsi_host *host,
struct samsung_dsim *dsi = host_to_dsi(host);
const struct samsung_dsim_plat_data *pdata = dsi->plat_data;
+ if (dsi->panel_bridge_added) {
+ drm_panel_bridge_remove(dsi->bridge.next_bridge);
+ dsi->panel_bridge_added = false;
+ }
+
if (pdata->host_ops && pdata->host_ops->detach)
pdata->host_ops->detach(dsi, device);
diff --git a/include/drm/bridge/samsung-dsim.h b/include/drm/bridge/samsung-dsim.h
index 03005e474704..3620f7aa9394 100644
--- a/include/drm/bridge/samsung-dsim.h
+++ b/include/drm/bridge/samsung-dsim.h
@@ -131,6 +131,8 @@ struct samsung_dsim {
const struct samsung_dsim_plat_data *plat_data;
void *priv;
+
+ bool panel_bridge_added; /* true iff next_bridge is a panel_bridge we created */
};
extern int samsung_dsim_probe(struct platform_device *pdev);
--
2.54.0
next prev parent reply other threads:[~2026-05-19 10:39 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-19 10:37 [PATCH 00/37] drm bridge hotplug Luca Ceresoli
2026-05-19 10:37 ` [PATCH 01/37] drm/connector: split drmm_connector_hdmi_init() in 3 parts Luca Ceresoli
2026-05-19 10:37 ` [PATCH 02/37] drm/connector: add drm_connector_hdmi_dynamic_init() Luca Ceresoli
2026-05-19 10:37 ` [PATCH 03/37] drm/display: bridge-connector: rename variable for consistency Luca Ceresoli
2026-05-19 10:37 ` [PATCH 04/37] drm/display: bridge-connector: store the drm_device pointer Luca Ceresoli
2026-05-19 10:37 ` [PATCH 05/37] drm/display: bridge-connector: split code creating the connector to a subfunction Luca Ceresoli
2026-05-19 10:37 ` [PATCH 06/37] drm/display: bridge-connector: use a drm_bridge_connector internally, not a drm_connector Luca Ceresoli
2026-05-19 10:37 ` [PATCH 07/37] drm/display: bridge-connector: extract drm_bridge_connector_get_bridges() Luca Ceresoli
2026-05-19 10:37 ` [PATCH 08/37] drm/display: bridge-connector: return int from drm_bridge_connector_get_bridges() Luca Ceresoli
2026-05-19 10:37 ` [PATCH 09/37] drm/display: bridge-connector: extract drm_bridge_connector_init_hdmi_audio_cec() Luca Ceresoli
2026-05-19 10:37 ` [PATCH 10/37] drm/display: bridge-connector: return int from drm_bridge_connector_init_hdmi_audio_cec() Luca Ceresoli
2026-05-19 10:37 ` [PATCH 11/37] drm/display: bridge-connector: return int from drm_bridge_connector_add_connector() Luca Ceresoli
2026-05-19 10:37 ` [PATCH 12/37] drm/display: bridge-connector: hoist error management to common code Luca Ceresoli
2026-05-19 10:37 ` [PATCH 13/37] drm/display: bridge-connector: move drm_bridge_connector_put_bridges() definition eariler Luca Ceresoli
2026-05-19 10:37 ` [PATCH 14/37] drm/display: bridge-connector: add non-drmm variant of drm_bridge_connector_put_bridges() Luca Ceresoli
2026-05-19 10:37 ` [PATCH 15/37] drm/display: bridge-connector: allocate the connector dynamically Luca Ceresoli
2026-05-19 10:37 ` [PATCH 16/37] drm/display: bridge-connector: move per-connector fields to the dynamic connector Luca Ceresoli
2026-05-19 10:37 ` [PATCH 17/37] drm/display: bridge-connector: protect dynconn creation and destruction with a mutex Luca Ceresoli
2026-05-19 10:37 ` Luca Ceresoli [this message]
2026-05-19 10:37 ` [PATCH 19/37] drm/bridge: samsung-dsim: move drm_bridge_add() call to probe Luca Ceresoli
2026-05-19 10:37 ` [PATCH 20/37] drm/bridge: samsung-dsim: attach: return -EPROBE_DEFER is next bridge not yet available Luca Ceresoli
2026-05-19 10:37 ` [PATCH 21/37] drm/bridge: initialize chain_node list head on allocation Luca Ceresoli
2026-05-19 10:37 ` [PATCH 22/37] drm/bridge: initialize chain_node list head on detach and attach errors Luca Ceresoli
2026-05-19 10:37 ` [PATCH 23/37] drm/encoder: add drm_encoder_cleanup_from() Luca Ceresoli
2026-05-19 10:37 ` [PATCH 24/37] drm/atomic: move drm_atomic_helper_disable_all() and drm_atomic_helper_shutdown() from drm_atomic_helper to drm_atomic Luca Ceresoli
2026-05-19 10:37 ` [PATCH 25/37] drm/bridge: shutdown and cleanup on bridge unplug Luca Ceresoli
2026-05-19 10:37 ` [PATCH 26/37] drm: event-notifier: add mechanism to notify about hotplug events Luca Ceresoli
2026-05-19 10:37 ` [PATCH 27/37] drm/bridge: notify about detached bridges Luca Ceresoli
2026-05-19 10:37 ` [PATCH 28/37] drm/mipi-dsi: turn DRM_MIPI_DSI into a tristate Luca Ceresoli
2026-05-19 10:37 ` [PATCH 29/37] drm/mipi-dsi: notify about DSI attach Luca Ceresoli
2026-05-19 10:37 ` [PATCH 30/37] drm/bridge: add drm_bridge_is_tail() to know whether a bridge completes the pipeline Luca Ceresoli
2026-05-19 10:37 ` [PATCH 31/37] drm/bridge: panel: implement .is_tail Luca Ceresoli
2026-05-19 15:12 ` Neil Armstrong
2026-05-19 10:37 ` [PATCH 32/37] drm/bridge: display-connector: " Luca Ceresoli
2026-05-19 10:37 ` [PATCH 33/37] drm/bridge: samsung-dsim: " Luca Ceresoli
2026-05-19 10:37 ` [PATCH 34/37] drm/bridge: ti-sn65dsi83: " Luca Ceresoli
2026-05-19 10:37 ` [PATCH 35/37] drm/bridge: drm_bridge_attach(): don't fail on -EPROBE_DEFER Luca Ceresoli
2026-05-19 10:37 ` [PATCH 36/37] drm/display: bridge-connector: handle bridge hotplug Luca Ceresoli
2026-05-19 10:37 ` [PATCH 37/37] drm/mxsfb/lcdif: enable " Luca Ceresoli
2026-06-01 15:44 ` [PATCH 00/37] drm " Luca Ceresoli
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