[PATCH 0/9] drm/bridge: get/put the bridge when looping over the encoder chain

[PATCH 0/9] drm/bridge: get/put the bridge when looping over the encoder chain

[Luca Ceresoli]

This series adds drm_bridge_get/put() calls for DRM bridges used when
looping over bridges in an encoder chain.

This is part of the work towards removal of bridges from a still existing
DRM pipeline without use-after-free. The grand plan was discussed in [1].
Here's the work breakdown (➜ marks the current series):

 1. ➜ add refcounting to DRM bridges (struct drm_bridge)
    (based on devm_drm_bridge_alloc() [0])
    A. ✔ add new alloc API and refcounting (in v6.16-rc1)
    B. ✔ convert all bridge drivers to new API (now in drm-misc-next)
    C. ✔ kunit tests (now in drm-misc-next)
    D. ✔ add get/put to drm_bridge_add/remove() + attach/detach()
         and warn on old allocation pattern (now in drm-misc-next)
    E. ➜ add get/put on drm_bridge accessors
       1. ✔ drm_bridge_chain_get_first_bridge() + add a cleanup action
       2. … drm_bridge_get_prev_bridge()
       3. … drm_bridge_get_next_bridge()
       4. ➜ drm_for_each_bridge_in_chain()
       5. drm_bridge_connector_init
       6. of_drm_find_bridge
       7. drm_of_find_panel_or_bridge, *_of_get_bridge
    F. debugfs improvements
 2. handle gracefully atomic updates during bridge removal
 3. … avoid DSI host drivers to have dangling pointers to DSI devices
 4. finish the hotplug bridge work, removing the "always-disconnected"
    connector, moving code to the core and potentially removing the
    hotplug-bridge itself (this needs to be clarified as points 1-3 are
    developed)

Most loops are based on drm_for_each_bridge_in_chain(), so add a scoped
variant that does not use an externally-declared iterator variable and
ensures that a reference to the bridge pointed to by the iterator is
taken/released before/after every iteration (and when breaking out of the
loop).

All conversions are trivial except for drm_bridge_connector_init() which
needs some preliminary cleanups (patches 1-2).

omapdrm/omap_encoder.c is the only driver iterating over the encoder bridge
chain starting from a specific bridge, instead of iterating over the whole
list. For this use case, add a drm_for_each_bridge_in_chain_from() variant.

This series depends on two fixes to bridge-connector:

 * commit 103578241512 ("drm/bridge-connector: Fix bridge in
   drm_connector_hdmi_audio_init()"), currently in drm/drm-fixes, not yet
   on drm-misc*

 * "drm/display: bridge-connector: correct CEC bridge pointers in
   drm_bridge_connector_init"
   (https://lore.kernel.org/lkml/20250719-fix-cec-bridges-v1-1-a60b1333c87d@oss.qualcomm.com/),
   not yet applied

[0] https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/0cc6aadd7fc1e629b715ea3d1ba537ef2da95eec
[1] https://lore.kernel.org/lkml/20250206-hotplug-drm-bridge-v6-0-9d6f2c9c3058@bootlin.com/t/#u

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
Luca Ceresoli (9):
      drm/display: bridge-connector: use scope-specific variable for the bridge pointer
      drm/display: bridge-connector: remove unused variable assignment
      drm/bridge: add drm_for_each_bridge_in_chain_scoped()
      drm/display: bridge-connector: use drm_for_each_bridge_in_chain_scoped()
      drm/atomic: use drm_for_each_bridge_in_chain_scoped()
      drm/bridge: use drm_for_each_bridge_in_chain_scoped()
      drm/bridge: remove drm_for_each_bridge_in_chain()
      drm/bridge: add drm_for_each_bridge_in_chain_from()
      drm/omap: use drm_for_each_bridge_in_chain_from()

 .clang-format                                  |  2 +-
 drivers/gpu/drm/display/drm_bridge_connector.c | 13 +++----
 drivers/gpu/drm/drm_atomic.c                   |  3 +-
 drivers/gpu/drm/drm_bridge.c                   |  3 +-
 drivers/gpu/drm/omapdrm/omap_encoder.c         |  4 +-
 include/drm/drm_bridge.h                       | 52 ++++++++++++++++++++++++--
 6 files changed, 58 insertions(+), 19 deletions(-)
---
base-commit: 46c366851a0b2159bdb97afcac04e5dec0cf09e8
change-id: 20250718-drm-bridge-alloc-getput-for_each_bridge-f141ae17b65a
prerequisite-change-id: 20250718-fix-cec-bridges-245d334d3712:v1
prerequisite-patch-id: df6d3d4a62c942703fab374bee85c49e4ac259cc
prerequisite-message-id: <20250620011616.118-1-kernel@airkyi.com>
prerequisite-patch-id: ba5a6a15ea02bcee387db0e92ffb4cd0e1fbf816

Best regards,
-- 
Luca Ceresoli <luca.ceresoli@bootlin.com>

[PATCH 1/9] drm/display: bridge-connector: use scope-specific variable for the bridge pointer

[Luca Ceresoli]

Currently drm_bridge_connector_init() reuses the 'bridge' variable, first
as a loop variable in the long drm_for_each_bridge_in_chain() and then in
the HDMI-specific code as a shortcut to bridge_connector->bridge_cec.

We are about to remove the 'bridge' loop variable for
drm_for_each_bridge_in_chain() by moving to a scoped version of the same
macro, which implies removing the 'bridge' variable from the main function
scope. Additionally reusing the variable can make such long function less
readable.

Similarly to what commit 6f727c838ea8 ("drm/bridge-connector: Fix bridge in
drm_connector_hdmi_audio_init()") already did for the audio HDMI bridge,
use n local variable inside the scopes where it is needed as a
bridge_connector->bridge_hdmi_cec shortcut to make its scope clearer as
well as to allow removing the 'bridge' variable in an upcoming commit.

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
 drivers/gpu/drm/display/drm_bridge_connector.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c
index 8c915427d0538435661d771940efe38b462027a1..3ddde53b28131c3ce026413eb5518e9c8ed08b4d 100644
--- a/drivers/gpu/drm/display/drm_bridge_connector.c
+++ b/drivers/gpu/drm/display/drm_bridge_connector.c
@@ -816,7 +816,7 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 
 	if (bridge_connector->bridge_hdmi_cec &&
 	    bridge_connector->bridge_hdmi_cec->ops & DRM_BRIDGE_OP_HDMI_CEC_NOTIFIER) {
-		bridge = bridge_connector->bridge_hdmi_cec;
+		struct drm_bridge *bridge = bridge_connector->bridge_hdmi_cec;
 
 		ret = drmm_connector_hdmi_cec_notifier_register(connector,
 								NULL,
@@ -827,7 +827,7 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 
 	if (bridge_connector->bridge_hdmi_cec &&
 	    bridge_connector->bridge_hdmi_cec->ops & DRM_BRIDGE_OP_HDMI_CEC_ADAPTER) {
-		bridge = bridge_connector->bridge_hdmi_cec;
+		struct drm_bridge *bridge = bridge_connector->bridge_hdmi_cec;
 
 		ret = drmm_connector_hdmi_cec_register(connector,
 						       &drm_bridge_connector_hdmi_cec_funcs,

-- 
2.50.1

[PATCH 2/9] drm/display: bridge-connector: remove unused variable assignment

[Luca Ceresoli]

The 'bridge' pointer started being assigned and used within this 'if' scope
in commit 0beba3f9d366 ("drm/bridge: connector: add support for HDMI codec
framework").

After that, commit 5d04b4188959 ("drm/bridge: split HDMI Audio from
DRM_BRIDGE_OP_HDMI") removed the code dereferencing it from the same 'if'
scope, but did not remove the assignment.

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
 drivers/gpu/drm/display/drm_bridge_connector.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c
index 3ddde53b28131c3ce026413eb5518e9c8ed08b4d..65d54019e5eab323ecd3dc568541ed1e1793a683 100644
--- a/drivers/gpu/drm/display/drm_bridge_connector.c
+++ b/drivers/gpu/drm/display/drm_bridge_connector.c
@@ -772,8 +772,6 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 		if (!connector->ycbcr_420_allowed)
 			supported_formats &= ~BIT(HDMI_COLORSPACE_YUV420);
 
-		bridge = bridge_connector->bridge_hdmi;
-
 		ret = drmm_connector_hdmi_init(drm, connector,
 					       bridge_connector->bridge_hdmi->vendor,
 					       bridge_connector->bridge_hdmi->product,

-- 
2.50.1

[PATCH 3/9] drm/bridge: add drm_for_each_bridge_in_chain_scoped()

[Luca Ceresoli]

Add variant of drm_for_each_bridge_in_chain() that gets/puts the bridge
reference at the beginning/end of each iteration, and puts it if breaking
ot of the loop.

Note that this requires adding a new drm_bridge_get_next_bridge_and_put()
function because, unlike similar functions as __of_get_next_child(),
drm_bridge_get_next_bridge() gets the "next" pointer but does not put the
"prev" pointer, and some of its users rely on this.

Also deprecate drm_for_each_bridge_in_chain(), in preparation for removing
it after converting all users to the scoped version.

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

---

Note 1: drm_for_each_bridge_in_chain_scoped() could be renamed removing the
        _scoped suffix after removing all the users of the current macro
        and eventually the current macro itself. Even though this series is
        converting all users, I'd at least wait one kernel release before
        renaming, to minimize issues with existing patches which would fail
        building.

Note 2: Yes, the drm_bridge_get_next_bridge_and_put() name is ugly, but we
        do need a "next_bridge" function that does not put the "prev"
        bridge and one that does. Any proposal for a better name or a
        different implementation is welcome.
---
 .clang-format            |  1 +
 include/drm/drm_bridge.h | 41 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/.clang-format b/.clang-format
index 48405c54ef271e9546da08893d200a4cf48f3a55..1cac7d4976644c8f083f801e98f619782c2e23cc 100644
--- a/.clang-format
+++ b/.clang-format
@@ -168,6 +168,7 @@ ForEachMacros:
   - 'drm_exec_for_each_locked_object'
   - 'drm_exec_for_each_locked_object_reverse'
   - 'drm_for_each_bridge_in_chain'
+  - 'drm_for_each_bridge_in_chain_scoped'
   - 'drm_for_each_connector_iter'
   - 'drm_for_each_crtc'
   - 'drm_for_each_crtc_reverse'
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 717171d0e58725ed854209c3355260e415b4c5d7..990ef98011c96619b269787ebe01a2ad3b225c42 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -1358,10 +1358,51 @@ drm_bridge_chain_get_first_bridge(struct drm_encoder *encoder)
  *	    iteration
  *
  * Iterate over all bridges present in the bridge chain attached to @encoder.
+ *
+ * This is deprecated, do not use!
+ * New drivers shall use drm_for_each_bridge_in_chain_scoped().
  */
 #define drm_for_each_bridge_in_chain(encoder, bridge)			\
 	list_for_each_entry(bridge, &(encoder)->bridge_chain, chain_node)
 
+/**
+ * drm_bridge_get_next_bridge_and_put - Get the next bridge in the chain
+ *                                      and put the previous
+ * @bridge: bridge object
+ *
+ * Same as drm_bridge_get_next_bridge() but additionally puts the @bridge.
+ *
+ * RETURNS:
+ * the next bridge in the chain after @bridge, or NULL if @bridge is the last.
+ */
+static inline struct drm_bridge *
+drm_bridge_get_next_bridge_and_put(struct drm_bridge *bridge)
+{
+	struct drm_bridge *next = drm_bridge_get_next_bridge(bridge);
+
+	drm_bridge_put(bridge);
+
+	return next;
+}
+
+/**
+ * drm_for_each_bridge_in_chain_scoped - iterate over all bridges attached
+ *                                       to an encoder
+ * @encoder: the encoder to iterate bridges on
+ * @bridge: a bridge pointer updated to point to the current bridge at each
+ *	    iteration
+ *
+ * Iterate over all bridges present in the bridge chain attached to @encoder.
+ *
+ * Automatically gets/puts the bridge reference while iterating, and puts
+ * the reference even if returning or breaking in the middle of the loop.
+ */
+#define drm_for_each_bridge_in_chain_scoped(encoder, bridge)		\
+	for (struct drm_bridge *bridge __free(drm_bridge_put) =		\
+	     drm_bridge_chain_get_first_bridge(encoder);		\
+	     bridge;							\
+	     bridge = drm_bridge_get_next_bridge_and_put(bridge))
+
 enum drm_mode_status
 drm_bridge_chain_mode_valid(struct drm_bridge *bridge,
 			    const struct drm_display_info *info,

-- 
2.50.1

[PATCH 4/9] drm/display: bridge-connector: use drm_for_each_bridge_in_chain_scoped()

[Luca Ceresoli]

Use drm_for_each_bridge_in_chain_scoped() instead of
drm_for_each_bridge_in_chain() to ensure the bridge being looped on is
refcounted.

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
 drivers/gpu/drm/display/drm_bridge_connector.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c
index 65d54019e5eab323ecd3dc568541ed1e1793a683..760ee00b6b02192dc1e59c213ef043a6bb9e3b60 100644
--- a/drivers/gpu/drm/display/drm_bridge_connector.c
+++ b/drivers/gpu/drm/display/drm_bridge_connector.c
@@ -136,10 +136,9 @@ static void drm_bridge_connector_hpd_notify(struct drm_connector *connector,
 {
 	struct drm_bridge_connector *bridge_connector =
 		to_drm_bridge_connector(connector);
-	struct drm_bridge *bridge;
 
 	/* Notify all bridges in the pipeline of hotplug events. */
-	drm_for_each_bridge_in_chain(bridge_connector->encoder, bridge) {
+	drm_for_each_bridge_in_chain_scoped(bridge_connector->encoder, bridge) {
 		if (bridge->funcs->hpd_notify)
 			bridge->funcs->hpd_notify(bridge, status);
 	}
@@ -638,7 +637,7 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 	struct drm_bridge_connector *bridge_connector;
 	struct drm_connector *connector;
 	struct i2c_adapter *ddc = NULL;
-	struct drm_bridge *bridge, *panel_bridge = NULL;
+	struct drm_bridge *panel_bridge = NULL;
 	unsigned int supported_formats = BIT(HDMI_COLORSPACE_RGB);
 	unsigned int max_bpc = 8;
 	int connector_type;
@@ -665,7 +664,7 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 	 * detection are available, we don't support hotplug detection at all.
 	 */
 	connector_type = DRM_MODE_CONNECTOR_Unknown;
-	drm_for_each_bridge_in_chain(encoder, bridge) {
+	drm_for_each_bridge_in_chain_scoped(encoder, bridge) {
 		if (!bridge->interlace_allowed)
 			connector->interlace_allowed = false;
 		if (!bridge->ycbcr_420_allowed)

-- 
2.50.1

[PATCH 5/9] drm/atomic: use drm_for_each_bridge_in_chain_scoped()

[Luca Ceresoli]

Use drm_for_each_bridge_in_chain_scoped() instead of
drm_for_each_bridge_in_chain() to ensure the bridge being looped on is
refcounted.

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
 drivers/gpu/drm/drm_atomic.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index cd15cf52f0c9144711da5879da57884674aea9e4..ed5359a71f7e2cd8fa52b993e62ee65f8fed4537 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -1308,7 +1308,6 @@ drm_atomic_add_encoder_bridges(struct drm_atomic_state *state,
 			       struct drm_encoder *encoder)
 {
 	struct drm_bridge_state *bridge_state;
-	struct drm_bridge *bridge;
 
 	if (!encoder)
 		return 0;
@@ -1317,7 +1316,7 @@ drm_atomic_add_encoder_bridges(struct drm_atomic_state *state,
 		       "Adding all bridges for [encoder:%d:%s] to %p\n",
 		       encoder->base.id, encoder->name, state);
 
-	drm_for_each_bridge_in_chain(encoder, bridge) {
+	drm_for_each_bridge_in_chain_scoped(encoder, bridge) {
 		/* Skip bridges that don't implement the atomic state hooks. */
 		if (!bridge->funcs->atomic_duplicate_state)
 			continue;

-- 
2.50.1

[PATCH 6/9] drm/bridge: use drm_for_each_bridge_in_chain_scoped()

[Luca Ceresoli]

Use drm_for_each_bridge_in_chain_scoped() instead of
drm_for_each_bridge_in_chain() to ensure the bridge being looped on is
refcounted.

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
 drivers/gpu/drm/drm_bridge.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index dd45d9b504d8f2802f4ee93e4b4d893d8535abea..297e8cde585c685e5105f8e6060ae7c2371dea00 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -1476,10 +1476,9 @@ static int encoder_bridges_show(struct seq_file *m, void *data)
 {
 	struct drm_encoder *encoder = m->private;
 	struct drm_printer p = drm_seq_file_printer(m);
-	struct drm_bridge *bridge;
 	unsigned int idx = 0;
 
-	drm_for_each_bridge_in_chain(encoder, bridge)
+	drm_for_each_bridge_in_chain_scoped(encoder, bridge)
 		drm_bridge_debugfs_show_bridge(&p, bridge, idx++);
 
 	return 0;

-- 
2.50.1

[PATCH 7/9] drm/bridge: remove drm_for_each_bridge_in_chain()

[Luca Ceresoli]

All users have been replaced by drm_for_each_bridge_in_chain_scoped().

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
 .clang-format            |  1 -
 include/drm/drm_bridge.h | 14 --------------
 2 files changed, 15 deletions(-)

diff --git a/.clang-format b/.clang-format
index 1cac7d4976644c8f083f801e98f619782c2e23cc..d5c05db1a0d96476b711b95912d2b82b2e780397 100644
--- a/.clang-format
+++ b/.clang-format
@@ -167,7 +167,6 @@ ForEachMacros:
   - 'drm_connector_for_each_possible_encoder'
   - 'drm_exec_for_each_locked_object'
   - 'drm_exec_for_each_locked_object_reverse'
-  - 'drm_for_each_bridge_in_chain'
   - 'drm_for_each_bridge_in_chain_scoped'
   - 'drm_for_each_connector_iter'
   - 'drm_for_each_crtc'
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 990ef98011c96619b269787ebe01a2ad3b225c42..0a45ed862ca3293bd0b12dacf3ba2c5429800d00 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -1351,20 +1351,6 @@ drm_bridge_chain_get_first_bridge(struct drm_encoder *encoder)
 						       struct drm_bridge, chain_node));
 }
 
-/**
- * drm_for_each_bridge_in_chain() - Iterate over all bridges present in a chain
- * @encoder: the encoder to iterate bridges on
- * @bridge: a bridge pointer updated to point to the current bridge at each
- *	    iteration
- *
- * Iterate over all bridges present in the bridge chain attached to @encoder.
- *
- * This is deprecated, do not use!
- * New drivers shall use drm_for_each_bridge_in_chain_scoped().
- */
-#define drm_for_each_bridge_in_chain(encoder, bridge)			\
-	list_for_each_entry(bridge, &(encoder)->bridge_chain, chain_node)
-
 /**
  * drm_bridge_get_next_bridge_and_put - Get the next bridge in the chain
  *                                      and put the previous

-- 
2.50.1

[PATCH 8/9] drm/bridge: add drm_for_each_bridge_in_chain_from()

[Luca Ceresoli]

Add variant of drm_for_each_bridge_in_chain_scoped() that iterates on the
encoder bridge from a given bridge until the end of the chain.

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
 include/drm/drm_bridge.h | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 0a45ed862ca3293bd0b12dacf3ba2c5429800d00..b271e1204c002f8dba080448583d75612f22a366 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -1389,6 +1389,25 @@ drm_bridge_get_next_bridge_and_put(struct drm_bridge *bridge)
 	     bridge;							\
 	     bridge = drm_bridge_get_next_bridge_and_put(bridge))
 
+/**
+ * drm_for_each_bridge_in_chain_from - iterate over all bridges starting
+ *                                     from the given bridge
+ * @first_bridge: the bridge to start from
+ * @bridge: a bridge pointer updated to point to the current bridge at each
+ *	    iteration
+ *
+ * Iterate over all bridges in the encoder chain starting from
+ * @first_bridge, included.
+ *
+ * Automatically gets/puts the bridge reference while iterating, and puts
+ * the reference even if returning or breaking in the middle of the loop.
+ */
+#define drm_for_each_bridge_in_chain_from(first_bridge, bridge)		\
+	for (struct drm_bridge *bridge __free(drm_bridge_put) =		\
+		     drm_bridge_get(first_bridge);			\
+	     bridge;							\
+	     bridge = drm_bridge_get_next_bridge_and_put(bridge))
+
 enum drm_mode_status
 drm_bridge_chain_mode_valid(struct drm_bridge *bridge,
 			    const struct drm_display_info *info,

-- 
2.50.1

[PATCH 9/9] drm/omap: use drm_for_each_bridge_in_chain_from()

[Luca Ceresoli]

Use drm_for_each_bridge_in_chain_from _scoped() instead of an open-coded
loop based on drm_bridge_get_next_bridge() to ensure the bridge being
looped on is refcounted and simplify the driver code.

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
 drivers/gpu/drm/omapdrm/omap_encoder.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/omapdrm/omap_encoder.c b/drivers/gpu/drm/omapdrm/omap_encoder.c
index 4dd05bc732daebcedbfcbbc9ba7dffee7415bdfc..195715b162e38ea0cd0870f3dd79342a8cbf218b 100644
--- a/drivers/gpu/drm/omapdrm/omap_encoder.c
+++ b/drivers/gpu/drm/omapdrm/omap_encoder.c
@@ -77,7 +77,6 @@ static void omap_encoder_mode_set(struct drm_encoder *encoder,
 	struct omap_dss_device *output = omap_encoder->output;
 	struct drm_device *dev = encoder->dev;
 	struct drm_connector *connector;
-	struct drm_bridge *bridge;
 	struct videomode vm = { 0 };
 	u32 bus_flags;
 
@@ -97,8 +96,7 @@ static void omap_encoder_mode_set(struct drm_encoder *encoder,
 	 *
 	 * A better solution is to use DRM's bus-flags through the whole driver.
 	 */
-	for (bridge = output->bridge; bridge;
-	     bridge = drm_bridge_get_next_bridge(bridge)) {
+	drm_for_each_bridge_in_chain_from(output->bridge, bridge) {
 		if (!bridge->timings)
 			continue;
 

-- 
2.50.1