[PATCH v8 0/2] drm: show "all" bridges in debugfs

[PATCH v8 0/2] drm: show "all" bridges in debugfs

[Luca Ceresoli]

This series adds a /sys/kernel/debug/dri/bridges file showing all bridges
between drm_bridge_add() and drm_bridge_remove(), which might not be bound
to any encoder and thus not visible anywhere in debugfs.

It also cleans up the DRM bridge debugfs code by moving code to
drm_bridge.c.

Luca

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
Changes in v8:
- moved more code to drm_bridge.c, which makes adding '#if CONFIG_DEBUG_FS' unnecessary
- a small fix to a harmless bug
- Link to v7: https://lore.kernel.org/r/20250225-drm-debugfs-show-all-bridges-v7-0-8826037ada37@bootlin.com

This series was initially part of v6 of this other series:
- Link to v6: https://lore.kernel.org/dri-devel/20250206-hotplug-drm-bridge-v6-0-9d6f2c9c3058@bootlin.com/

---
Luca Ceresoli (2):
      drm/bridge: move bridges_show logic from drm_debugfs.c
      drm/debugfs: add top-level 'bridges' file showing all added bridges

 drivers/gpu/drm/drm_bridge.c  | 70 +++++++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_debugfs.c | 38 +----------------------
 drivers/gpu/drm/drm_drv.c     |  2 ++
 include/drm/drm_bridge.h      |  3 ++
 4 files changed, 76 insertions(+), 37 deletions(-)
---
base-commit: b439ab75b6382f5c34aec6e87435cf7e58e72a35
change-id: 20250225-drm-debugfs-show-all-bridges-642e870b71e7

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

[PATCH v8 1/2] drm/bridge: move bridges_show logic from drm_debugfs.c

[Luca Ceresoli]

In preparation to expose more info about bridges in debugfs, which will
require more insight into drm_bridge data structures, move the bridges_show
code to drm_bridge.c.

Suggested-by: Jani Nikula <jani.nikula@linux.intel.com>
Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

---

Changed in v8:
 - add the file in drm_bridge.c, which avois the added #if CONFIG_DEBUG_FS

This patch was added in v7.
---
 drivers/gpu/drm/drm_bridge.c  | 42 ++++++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_debugfs.c | 38 +-------------------------------------
 include/drm/drm_bridge.h      |  2 ++
 3 files changed, 45 insertions(+), 37 deletions(-)

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index 241a384ebce39b4a3db58c208af27960904fc662..a6bf1a565e3c3a8d24de60448972849f6d86ba72 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -21,6 +21,7 @@
  * DEALINGS IN THE SOFTWARE.
  */
 
+#include <linux/debugfs.h>
 #include <linux/err.h>
 #include <linux/media-bus-format.h>
 #include <linux/module.h>
@@ -1335,6 +1336,47 @@ struct drm_bridge *of_drm_find_bridge(struct device_node *np)
 EXPORT_SYMBOL(of_drm_find_bridge);
 #endif
 
+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_printf(&p, "bridge[%u]: %ps\n", idx++, bridge->funcs);
+		drm_printf(&p, "\ttype: [%d] %s\n",
+			   bridge->type,
+			   drm_get_connector_type_name(bridge->type));
+
+		if (bridge->of_node)
+			drm_printf(&p, "\tOF: %pOFfc\n", bridge->of_node);
+
+		drm_printf(&p, "\tops: [0x%x]", bridge->ops);
+		if (bridge->ops & DRM_BRIDGE_OP_DETECT)
+			drm_puts(&p, " detect");
+		if (bridge->ops & DRM_BRIDGE_OP_EDID)
+			drm_puts(&p, " edid");
+		if (bridge->ops & DRM_BRIDGE_OP_HPD)
+			drm_puts(&p, " hpd");
+		if (bridge->ops & DRM_BRIDGE_OP_MODES)
+			drm_puts(&p, " modes");
+		if (bridge->ops & DRM_BRIDGE_OP_HDMI)
+			drm_puts(&p, " hdmi");
+		drm_puts(&p, "\n");
+	}
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(encoder_bridges);
+
+void drm_bridge_debugfs_encoder_params(struct dentry *root,
+				       struct drm_encoder *encoder)
+{
+	/* bridges list */
+	debugfs_create_file("bridges", 0444, root, encoder, &encoder_bridges_fops);
+}
+
 MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>");
 MODULE_DESCRIPTION("DRM bridge infrastructure");
 MODULE_LICENSE("GPL and additional rights");
diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c
index 6b2178864c7ee12db9aa1f562e106b2f604439f8..3dfd8b34dceb7a5b8f11e3072a1eaef430869722 100644
--- a/drivers/gpu/drm/drm_debugfs.c
+++ b/drivers/gpu/drm/drm_debugfs.c
@@ -740,40 +740,6 @@ void drm_debugfs_crtc_remove(struct drm_crtc *crtc)
 	crtc->debugfs_entry = NULL;
 }
 
-static int 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_printf(&p, "bridge[%u]: %ps\n", idx++, bridge->funcs);
-		drm_printf(&p, "\ttype: [%d] %s\n",
-			   bridge->type,
-			   drm_get_connector_type_name(bridge->type));
-
-		if (bridge->of_node)
-			drm_printf(&p, "\tOF: %pOFfc\n", bridge->of_node);
-
-		drm_printf(&p, "\tops: [0x%x]", bridge->ops);
-		if (bridge->ops & DRM_BRIDGE_OP_DETECT)
-			drm_puts(&p, " detect");
-		if (bridge->ops & DRM_BRIDGE_OP_EDID)
-			drm_puts(&p, " edid");
-		if (bridge->ops & DRM_BRIDGE_OP_HPD)
-			drm_puts(&p, " hpd");
-		if (bridge->ops & DRM_BRIDGE_OP_MODES)
-			drm_puts(&p, " modes");
-		if (bridge->ops & DRM_BRIDGE_OP_HDMI)
-			drm_puts(&p, " hdmi");
-		drm_puts(&p, "\n");
-	}
-
-	return 0;
-}
-DEFINE_SHOW_ATTRIBUTE(bridges);
-
 void drm_debugfs_encoder_add(struct drm_encoder *encoder)
 {
 	struct drm_minor *minor = encoder->dev->primary;
@@ -789,9 +755,7 @@ void drm_debugfs_encoder_add(struct drm_encoder *encoder)
 
 	encoder->debugfs_entry = root;
 
-	/* bridges list */
-	debugfs_create_file("bridges", 0444, root, encoder,
-			    &bridges_fops);
+	drm_bridge_debugfs_encoder_params(root, encoder);
 
 	if (encoder->funcs && encoder->funcs->debugfs_init)
 		encoder->funcs->debugfs_init(encoder, root);
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 496dbbd2ad7edff7f091adfbe62de1e33ef0cf07..0890acfe04b99b1ccbbff10b507cb8c2b2705e06 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -1108,4 +1108,6 @@ static inline struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm,
 }
 #endif
 
+void drm_bridge_debugfs_encoder_params(struct dentry *root, struct drm_encoder *encoder);
+
 #endif

-- 
2.48.1

[PATCH v8 2/2] drm/debugfs: add top-level 'bridges' file showing all added bridges

[Luca Ceresoli]

The global bridges_list holding all the bridges between drm_bridge_add()
and drm_bridge_remove() cannot be inspected via debugfs. Add a file showing
it.

To avoid code duplication, move the code printing a bridge info to a common
function.

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

---

Changed in v8:
- add the file in drm_bridge.c, which avois the added #if CONFIG_DEBUG_FS
- fix incorrect (but harmless) idx increment in
  drm_bridge_debugfs_show_bridge()

Changed in v7:
- move implementation to drm_bridge.c to avoid exporting bridge_list and
  bridge_mutex

This patch was added in v6.
---
 drivers/gpu/drm/drm_bridge.c | 72 ++++++++++++++++++++++++++++++--------------
 drivers/gpu/drm/drm_drv.c    |  2 ++
 include/drm/drm_bridge.h     |  1 +
 3 files changed, 53 insertions(+), 22 deletions(-)

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index a6bf1a565e3c3a8d24de60448972849f6d86ba72..9c6e35d41ed54a14d5745e684a341c907ed84d6b 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -1336,6 +1336,49 @@ struct drm_bridge *of_drm_find_bridge(struct device_node *np)
 EXPORT_SYMBOL(of_drm_find_bridge);
 #endif
 
+static void drm_bridge_debugfs_show_bridge(struct drm_printer *p,
+					   struct drm_bridge *bridge,
+					   unsigned int idx)
+{
+	drm_printf(p, "bridge[%u]: %ps\n", idx, bridge->funcs);
+	drm_printf(p, "\ttype: [%d] %s\n",
+		   bridge->type,
+		   drm_get_connector_type_name(bridge->type));
+
+	if (bridge->of_node)
+		drm_printf(p, "\tOF: %pOFfc\n", bridge->of_node);
+
+	drm_printf(p, "\tops: [0x%x]", bridge->ops);
+	if (bridge->ops & DRM_BRIDGE_OP_DETECT)
+		drm_puts(p, " detect");
+	if (bridge->ops & DRM_BRIDGE_OP_EDID)
+		drm_puts(p, " edid");
+	if (bridge->ops & DRM_BRIDGE_OP_HPD)
+		drm_puts(p, " hpd");
+	if (bridge->ops & DRM_BRIDGE_OP_MODES)
+		drm_puts(p, " modes");
+	if (bridge->ops & DRM_BRIDGE_OP_HDMI)
+		drm_puts(p, " hdmi");
+	drm_puts(p, "\n");
+}
+
+static int allbridges_show(struct seq_file *m, void *data)
+{
+	struct drm_printer p = drm_seq_file_printer(m);
+	struct drm_bridge *bridge;
+	unsigned int idx = 0;
+
+	mutex_lock(&bridge_lock);
+
+	list_for_each_entry(bridge, &bridge_list, list)
+		drm_bridge_debugfs_show_bridge(&p, bridge, idx++);
+
+	mutex_unlock(&bridge_lock);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(allbridges);
+
 static int encoder_bridges_show(struct seq_file *m, void *data)
 {
 	struct drm_encoder *encoder = m->private;
@@ -1343,33 +1386,18 @@ static int encoder_bridges_show(struct seq_file *m, void *data)
 	struct drm_bridge *bridge;
 	unsigned int idx = 0;
 
-	drm_for_each_bridge_in_chain(encoder, bridge) {
-		drm_printf(&p, "bridge[%u]: %ps\n", idx++, bridge->funcs);
-		drm_printf(&p, "\ttype: [%d] %s\n",
-			   bridge->type,
-			   drm_get_connector_type_name(bridge->type));
-
-		if (bridge->of_node)
-			drm_printf(&p, "\tOF: %pOFfc\n", bridge->of_node);
-
-		drm_printf(&p, "\tops: [0x%x]", bridge->ops);
-		if (bridge->ops & DRM_BRIDGE_OP_DETECT)
-			drm_puts(&p, " detect");
-		if (bridge->ops & DRM_BRIDGE_OP_EDID)
-			drm_puts(&p, " edid");
-		if (bridge->ops & DRM_BRIDGE_OP_HPD)
-			drm_puts(&p, " hpd");
-		if (bridge->ops & DRM_BRIDGE_OP_MODES)
-			drm_puts(&p, " modes");
-		if (bridge->ops & DRM_BRIDGE_OP_HDMI)
-			drm_puts(&p, " hdmi");
-		drm_puts(&p, "\n");
-	}
+	drm_for_each_bridge_in_chain(encoder, bridge)
+		drm_bridge_debugfs_show_bridge(&p, bridge, idx++);
 
 	return 0;
 }
 DEFINE_SHOW_ATTRIBUTE(encoder_bridges);
 
+void drm_bridge_debugfs_params(struct dentry *root)
+{
+	debugfs_create_file("bridges", 0444, root, NULL, &allbridges_fops);
+}
+
 void drm_bridge_debugfs_encoder_params(struct dentry *root,
 				       struct drm_encoder *encoder)
 {
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 3cf440eee8a2ab3de134d925db8f1d2ce68062b7..22e8cd0a6a37a0ac25535e9d570da25571b0b2bc 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -38,6 +38,7 @@
 #include <linux/xarray.h>
 
 #include <drm/drm_accel.h>
+#include <drm/drm_bridge.h>
 #include <drm/drm_cache.h>
 #include <drm/drm_client_event.h>
 #include <drm/drm_color_mgmt.h>
@@ -1120,6 +1121,7 @@ static int __init drm_core_init(void)
 	}
 
 	drm_debugfs_root = debugfs_create_dir("dri", NULL);
+	drm_bridge_debugfs_params(drm_debugfs_root);
 
 	ret = register_chrdev(DRM_MAJOR, "drm", &drm_stub_fops);
 	if (ret < 0)
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 0890acfe04b99b1ccbbff10b507cb8c2b2705e06..2a99d70865571f24db0ca75c758cfd09d3a5d459 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -1108,6 +1108,7 @@ static inline struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm,
 }
 #endif
 
+void drm_bridge_debugfs_params(struct dentry *root);
 void drm_bridge_debugfs_encoder_params(struct dentry *root, struct drm_encoder *encoder);
 
 #endif

-- 
2.48.1

Re: [PATCH v8 1/2] drm/bridge: move bridges_show logic from drm_debugfs.c

[Jani Nikula]

On Wed, 26 Feb 2025, Luca Ceresoli <luca.ceresoli@bootlin.com> wrote:
> In preparation to expose more info about bridges in debugfs, which will
> require more insight into drm_bridge data structures, move the bridges_show
> code to drm_bridge.c.
>
> Suggested-by: Jani Nikula <jani.nikula@linux.intel.com>
> Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
>
> ---
>
> Changed in v8:
>  - add the file in drm_bridge.c, which avois the added #if CONFIG_DEBUG_FS
>
> This patch was added in v7.
> ---
>  drivers/gpu/drm/drm_bridge.c  | 42 ++++++++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/drm_debugfs.c | 38 +-------------------------------------
>  include/drm/drm_bridge.h      |  2 ++
>  3 files changed, 45 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index 241a384ebce39b4a3db58c208af27960904fc662..a6bf1a565e3c3a8d24de60448972849f6d86ba72 100644
> --- a/drivers/gpu/drm/drm_bridge.c
> +++ b/drivers/gpu/drm/drm_bridge.c
> @@ -21,6 +21,7 @@
>   * DEALINGS IN THE SOFTWARE.
>   */
>  
> +#include <linux/debugfs.h>
>  #include <linux/err.h>
>  #include <linux/media-bus-format.h>
>  #include <linux/module.h>
> @@ -1335,6 +1336,47 @@ struct drm_bridge *of_drm_find_bridge(struct device_node *np)
>  EXPORT_SYMBOL(of_drm_find_bridge);
>  #endif
>  
> +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_printf(&p, "bridge[%u]: %ps\n", idx++, bridge->funcs);
> +		drm_printf(&p, "\ttype: [%d] %s\n",
> +			   bridge->type,
> +			   drm_get_connector_type_name(bridge->type));
> +
> +		if (bridge->of_node)
> +			drm_printf(&p, "\tOF: %pOFfc\n", bridge->of_node);
> +
> +		drm_printf(&p, "\tops: [0x%x]", bridge->ops);
> +		if (bridge->ops & DRM_BRIDGE_OP_DETECT)
> +			drm_puts(&p, " detect");
> +		if (bridge->ops & DRM_BRIDGE_OP_EDID)
> +			drm_puts(&p, " edid");
> +		if (bridge->ops & DRM_BRIDGE_OP_HPD)
> +			drm_puts(&p, " hpd");
> +		if (bridge->ops & DRM_BRIDGE_OP_MODES)
> +			drm_puts(&p, " modes");
> +		if (bridge->ops & DRM_BRIDGE_OP_HDMI)
> +			drm_puts(&p, " hdmi");
> +		drm_puts(&p, "\n");
> +	}
> +
> +	return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(encoder_bridges);
> +
> +void drm_bridge_debugfs_encoder_params(struct dentry *root,
> +				       struct drm_encoder *encoder)
> +{
> +	/* bridges list */
> +	debugfs_create_file("bridges", 0444, root, encoder, &encoder_bridges_fops);

The function could look at encoder->debugfs_entry instead of requiring
the root parameter, but that's neither here nor there.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> +}
> +
>  MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>");
>  MODULE_DESCRIPTION("DRM bridge infrastructure");
>  MODULE_LICENSE("GPL and additional rights");
> diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c
> index 6b2178864c7ee12db9aa1f562e106b2f604439f8..3dfd8b34dceb7a5b8f11e3072a1eaef430869722 100644
> --- a/drivers/gpu/drm/drm_debugfs.c
> +++ b/drivers/gpu/drm/drm_debugfs.c
> @@ -740,40 +740,6 @@ void drm_debugfs_crtc_remove(struct drm_crtc *crtc)
>  	crtc->debugfs_entry = NULL;
>  }
>  
> -static int 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_printf(&p, "bridge[%u]: %ps\n", idx++, bridge->funcs);
> -		drm_printf(&p, "\ttype: [%d] %s\n",
> -			   bridge->type,
> -			   drm_get_connector_type_name(bridge->type));
> -
> -		if (bridge->of_node)
> -			drm_printf(&p, "\tOF: %pOFfc\n", bridge->of_node);
> -
> -		drm_printf(&p, "\tops: [0x%x]", bridge->ops);
> -		if (bridge->ops & DRM_BRIDGE_OP_DETECT)
> -			drm_puts(&p, " detect");
> -		if (bridge->ops & DRM_BRIDGE_OP_EDID)
> -			drm_puts(&p, " edid");
> -		if (bridge->ops & DRM_BRIDGE_OP_HPD)
> -			drm_puts(&p, " hpd");
> -		if (bridge->ops & DRM_BRIDGE_OP_MODES)
> -			drm_puts(&p, " modes");
> -		if (bridge->ops & DRM_BRIDGE_OP_HDMI)
> -			drm_puts(&p, " hdmi");
> -		drm_puts(&p, "\n");
> -	}
> -
> -	return 0;
> -}
> -DEFINE_SHOW_ATTRIBUTE(bridges);
> -
>  void drm_debugfs_encoder_add(struct drm_encoder *encoder)
>  {
>  	struct drm_minor *minor = encoder->dev->primary;
> @@ -789,9 +755,7 @@ void drm_debugfs_encoder_add(struct drm_encoder *encoder)
>  
>  	encoder->debugfs_entry = root;
>  
> -	/* bridges list */
> -	debugfs_create_file("bridges", 0444, root, encoder,
> -			    &bridges_fops);
> +	drm_bridge_debugfs_encoder_params(root, encoder);
>  
>  	if (encoder->funcs && encoder->funcs->debugfs_init)
>  		encoder->funcs->debugfs_init(encoder, root);
> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> index 496dbbd2ad7edff7f091adfbe62de1e33ef0cf07..0890acfe04b99b1ccbbff10b507cb8c2b2705e06 100644
> --- a/include/drm/drm_bridge.h
> +++ b/include/drm/drm_bridge.h
> @@ -1108,4 +1108,6 @@ static inline struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm,
>  }
>  #endif
>  
> +void drm_bridge_debugfs_encoder_params(struct dentry *root, struct drm_encoder *encoder);
> +
>  #endif

-- 
Jani Nikula, Intel

Re: [PATCH v8 2/2] drm/debugfs: add top-level 'bridges' file showing all added bridges

[Jani Nikula]

On Wed, 26 Feb 2025, Luca Ceresoli <luca.ceresoli@bootlin.com> wrote:
> The global bridges_list holding all the bridges between drm_bridge_add()
> and drm_bridge_remove() cannot be inspected via debugfs. Add a file showing
> it.
>
> To avoid code duplication, move the code printing a bridge info to a common
> function.

Going forward, please separate refactoring (extracting the function)
from the functional changes (adding the new debugfs) to independent
patches. It's just easier to review.

Anyway, I reviewed this one, so no need to roll another version.

And thanks for doing this; I believe the end result is better.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

>
> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
>
> ---
>
> Changed in v8:
> - add the file in drm_bridge.c, which avois the added #if CONFIG_DEBUG_FS
> - fix incorrect (but harmless) idx increment in
>   drm_bridge_debugfs_show_bridge()
>
> Changed in v7:
> - move implementation to drm_bridge.c to avoid exporting bridge_list and
>   bridge_mutex
>
> This patch was added in v6.
> ---
>  drivers/gpu/drm/drm_bridge.c | 72 ++++++++++++++++++++++++++++++--------------
>  drivers/gpu/drm/drm_drv.c    |  2 ++
>  include/drm/drm_bridge.h     |  1 +
>  3 files changed, 53 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index a6bf1a565e3c3a8d24de60448972849f6d86ba72..9c6e35d41ed54a14d5745e684a341c907ed84d6b 100644
> --- a/drivers/gpu/drm/drm_bridge.c
> +++ b/drivers/gpu/drm/drm_bridge.c
> @@ -1336,6 +1336,49 @@ struct drm_bridge *of_drm_find_bridge(struct device_node *np)
>  EXPORT_SYMBOL(of_drm_find_bridge);
>  #endif
>  
> +static void drm_bridge_debugfs_show_bridge(struct drm_printer *p,
> +					   struct drm_bridge *bridge,
> +					   unsigned int idx)
> +{
> +	drm_printf(p, "bridge[%u]: %ps\n", idx, bridge->funcs);
> +	drm_printf(p, "\ttype: [%d] %s\n",
> +		   bridge->type,
> +		   drm_get_connector_type_name(bridge->type));
> +
> +	if (bridge->of_node)
> +		drm_printf(p, "\tOF: %pOFfc\n", bridge->of_node);
> +
> +	drm_printf(p, "\tops: [0x%x]", bridge->ops);
> +	if (bridge->ops & DRM_BRIDGE_OP_DETECT)
> +		drm_puts(p, " detect");
> +	if (bridge->ops & DRM_BRIDGE_OP_EDID)
> +		drm_puts(p, " edid");
> +	if (bridge->ops & DRM_BRIDGE_OP_HPD)
> +		drm_puts(p, " hpd");
> +	if (bridge->ops & DRM_BRIDGE_OP_MODES)
> +		drm_puts(p, " modes");
> +	if (bridge->ops & DRM_BRIDGE_OP_HDMI)
> +		drm_puts(p, " hdmi");
> +	drm_puts(p, "\n");
> +}
> +
> +static int allbridges_show(struct seq_file *m, void *data)
> +{
> +	struct drm_printer p = drm_seq_file_printer(m);
> +	struct drm_bridge *bridge;
> +	unsigned int idx = 0;
> +
> +	mutex_lock(&bridge_lock);
> +
> +	list_for_each_entry(bridge, &bridge_list, list)
> +		drm_bridge_debugfs_show_bridge(&p, bridge, idx++);
> +
> +	mutex_unlock(&bridge_lock);
> +
> +	return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(allbridges);
> +
>  static int encoder_bridges_show(struct seq_file *m, void *data)
>  {
>  	struct drm_encoder *encoder = m->private;
> @@ -1343,33 +1386,18 @@ static int encoder_bridges_show(struct seq_file *m, void *data)
>  	struct drm_bridge *bridge;
>  	unsigned int idx = 0;
>  
> -	drm_for_each_bridge_in_chain(encoder, bridge) {
> -		drm_printf(&p, "bridge[%u]: %ps\n", idx++, bridge->funcs);
> -		drm_printf(&p, "\ttype: [%d] %s\n",
> -			   bridge->type,
> -			   drm_get_connector_type_name(bridge->type));
> -
> -		if (bridge->of_node)
> -			drm_printf(&p, "\tOF: %pOFfc\n", bridge->of_node);
> -
> -		drm_printf(&p, "\tops: [0x%x]", bridge->ops);
> -		if (bridge->ops & DRM_BRIDGE_OP_DETECT)
> -			drm_puts(&p, " detect");
> -		if (bridge->ops & DRM_BRIDGE_OP_EDID)
> -			drm_puts(&p, " edid");
> -		if (bridge->ops & DRM_BRIDGE_OP_HPD)
> -			drm_puts(&p, " hpd");
> -		if (bridge->ops & DRM_BRIDGE_OP_MODES)
> -			drm_puts(&p, " modes");
> -		if (bridge->ops & DRM_BRIDGE_OP_HDMI)
> -			drm_puts(&p, " hdmi");
> -		drm_puts(&p, "\n");
> -	}
> +	drm_for_each_bridge_in_chain(encoder, bridge)
> +		drm_bridge_debugfs_show_bridge(&p, bridge, idx++);
>  
>  	return 0;
>  }
>  DEFINE_SHOW_ATTRIBUTE(encoder_bridges);
>  
> +void drm_bridge_debugfs_params(struct dentry *root)
> +{
> +	debugfs_create_file("bridges", 0444, root, NULL, &allbridges_fops);
> +}
> +
>  void drm_bridge_debugfs_encoder_params(struct dentry *root,
>  				       struct drm_encoder *encoder)
>  {
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index 3cf440eee8a2ab3de134d925db8f1d2ce68062b7..22e8cd0a6a37a0ac25535e9d570da25571b0b2bc 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -38,6 +38,7 @@
>  #include <linux/xarray.h>
>  
>  #include <drm/drm_accel.h>
> +#include <drm/drm_bridge.h>
>  #include <drm/drm_cache.h>
>  #include <drm/drm_client_event.h>
>  #include <drm/drm_color_mgmt.h>
> @@ -1120,6 +1121,7 @@ static int __init drm_core_init(void)
>  	}
>  
>  	drm_debugfs_root = debugfs_create_dir("dri", NULL);
> +	drm_bridge_debugfs_params(drm_debugfs_root);
>  
>  	ret = register_chrdev(DRM_MAJOR, "drm", &drm_stub_fops);
>  	if (ret < 0)
> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> index 0890acfe04b99b1ccbbff10b507cb8c2b2705e06..2a99d70865571f24db0ca75c758cfd09d3a5d459 100644
> --- a/include/drm/drm_bridge.h
> +++ b/include/drm/drm_bridge.h
> @@ -1108,6 +1108,7 @@ static inline struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm,
>  }
>  #endif
>  
> +void drm_bridge_debugfs_params(struct dentry *root);
>  void drm_bridge_debugfs_encoder_params(struct dentry *root, struct drm_encoder *encoder);
>  
>  #endif

-- 
Jani Nikula, Intel

Re: [PATCH v8 0/2] drm: show "all" bridges in debugfs

[Louis Chauvet]

On Wed, 26 Feb 2025 22:23:51 +0100, Luca Ceresoli wrote:
> This series adds a /sys/kernel/debug/dri/bridges file showing all bridges
> between drm_bridge_add() and drm_bridge_remove(), which might not be bound
> to any encoder and thus not visible anywhere in debugfs.
> 
> It also cleans up the DRM bridge debugfs code by moving code to
> drm_bridge.c.
> 
> [...]

Applied, thanks!

[1/2] drm/bridge: move bridges_show logic from drm_debugfs.c
      commit: 9497c5a0f7c26ff81f11df738a94c6b80f890c0a
[2/2] drm/debugfs: add top-level 'bridges' file showing all added bridges
      commit: eff0347e7c228335e9ff64aaf02c66957803af6a

Best regards,
-- 
Louis Chauvet <louis.chauvet@bootlin.com>