Re: [PATCH v3] drm/bridge: Add debugfs print for bridge chains
Hi Tomi,
Thank you for the patch.
On Mon, Jul 31, 2023 at 03:13:14PM +0300, Tomi Valkeinen wrote:
> DRM bridges are not visible to the userspace and it may not be
> immediately clear if the chain is somehow constructed incorrectly. I
> have had two separate instances of a bridge driver failing to do a
> drm_bridge_attach() call, resulting in the bridge connector not being
> part of the chain. In some situations this doesn't seem to cause issues,
> but it will if DRM_BRIDGE_ATTACH_NO_CONNECTOR flag is used.
>
> Add a debugfs file to print the bridge chains. For me, on this TI AM62
> based platform, I get the following output:
>
> encoder[39]
> bridge[0] type: 0, ops: 0x0
> bridge[1] type: 0, ops: 0x0, OF:
> /bus@f/i2c@2000/dsi@e:toshiba,tc358778
> bridge[2] type: 0, ops: 0x3, OF:
> /bus@f/i2c@2001/hdmi@48:lontium,lt8912b
> bridge[3] type: 11, ops: 0x7, OF: /hdmi-connector:hdmi-connector
>
> Signed-off-by: Tomi Valkeinen
> ---
> Changes in v3:
> - Use drm_for_each_bridge_in_chain()
> - Drop extra comment
> - Fix whitespace issue
> - Call drm_bridge_debugfs_init() only if the driver uses modeset
> - Drop #ifdef for drm_bridge_debugfs_init() declaration
> - Link to v2:
> https://lore.kernel.org/r/20230721-drm-bridge-chain-debugfs-v2-1-76df94347...@ideasonboard.com
>
> Changes in v2:
> - Fixed compilation issue when !CONFIG_OF
> - Link to v1:
> https://lore.kernel.org/r/20230721-drm-bridge-chain-debugfs-v1-1-8614ff7e8...@ideasonboard.com
> ---
> drivers/gpu/drm/drm_bridge.c | 46
> +++
> drivers/gpu/drm/drm_debugfs.c | 3 +++
> include/drm/drm_bridge.h | 3 +++
> 3 files changed, 52 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index c3d69af02e79..39e68e45bb12 100644
> --- a/drivers/gpu/drm/drm_bridge.c
> +++ b/drivers/gpu/drm/drm_bridge.c
> @@ -27,8 +27,10 @@
> #include
>
> #include
> +#include
> #include
> #include
> +#include
> #include
> #include
>
> @@ -1345,6 +1347,50 @@ struct drm_bridge *of_drm_find_bridge(struct
> device_node *np)
> EXPORT_SYMBOL(of_drm_find_bridge);
> #endif
>
> +#ifdef CONFIG_DEBUG_FS
> +static int drm_bridge_chains_info(struct seq_file *m, void *data)
> +{
> + struct drm_debugfs_entry *entry = m->private;
> + struct drm_device *dev = entry->dev;
> + struct drm_printer p = drm_seq_file_printer(m);
> + struct drm_mode_config *config = >mode_config;
> + struct drm_encoder *encoder;
> + unsigned int bridge_idx = 0;
> +
> + list_for_each_entry(encoder, >encoder_list, head) {
> + struct drm_bridge *bridge;
> +
> + drm_printf(, "encoder[%u]\n", encoder->base.id);
> +
> + drm_for_each_bridge_in_chain(encoder, bridge) {
> + drm_printf(, "\tbridge[%u] type: %u, ops: %#x",
> +bridge_idx, bridge->type, bridge->ops);
> +
> +#ifdef CONFIG_OF
> + if (bridge->of_node)
> + drm_printf(, ", OF: %pOFfc", bridge->of_node);
> +#endif
> +
> + drm_printf(, "\n");
> +
> + bridge_idx++;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static const struct drm_debugfs_info drm_bridge_debugfs_list[] = {
> + { "bridge_chains", drm_bridge_chains_info, 0 },
> +};
> +
> +void drm_bridge_debugfs_init(struct drm_minor *minor)
> +{
> + drm_debugfs_add_files(minor->dev, drm_bridge_debugfs_list,
> + ARRAY_SIZE(drm_bridge_debugfs_list));
> +}
> +#endif
> +
> MODULE_AUTHOR("Ajay Kumar ");
> 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 a3a488205009..3b1de2c61c89 100644
> --- a/drivers/gpu/drm/drm_debugfs.c
> +++ b/drivers/gpu/drm/drm_debugfs.c
> @@ -31,6 +31,7 @@
>
> #include
> #include
> +#include
> #include
> #include
> #include
> @@ -274,6 +275,8 @@ int drm_debugfs_init(struct drm_minor *minor, int
> minor_id,
>
> if (drm_drv_uses_atomic_modeset(dev)) {
> drm_atomic_debugfs_init(minor);
> +
You could drop the blank line, up to you.
> + drm_bridge_debugfs_init(minor);
> }
>
> if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> index bf964cdfb330..cb10ee108538 100644
> --- a/include/drm/drm_bridge.h
> +++ b/include/drm/drm_bridge.h
> @@ -949,4 +949,7 @@ static inline struct drm_bridge
> *drmm_of_get_bridge(struct drm_device *drm,
> }
> #endif
>
> +struct drm_minor;
Let's move this to tbe beginning of the file with the other forward
declarations. With this addressedn
Reviewed-by: Laurent Pinchart
> +void drm_bridge_debugfs_init(struct drm_minor *minor);
> +
> #endif
>
> ---
> base-commit: a0c64d153d687756c8719b8d10e609d62e1cb6fd
>
Re: [PATCH v3] drm/bridge: Add debugfs print for bridge chains
Hi Tomi,
Am Montag, 31. Juli 2023, 14:13:14 CEST schrieb Tomi Valkeinen:
> DRM bridges are not visible to the userspace and it may not be
> immediately clear if the chain is somehow constructed incorrectly. I
> have had two separate instances of a bridge driver failing to do a
> drm_bridge_attach() call, resulting in the bridge connector not being
> part of the chain. In some situations this doesn't seem to cause issues,
> but it will if DRM_BRIDGE_ATTACH_NO_CONNECTOR flag is used.
>
> Add a debugfs file to print the bridge chains. For me, on this TI AM62
> based platform, I get the following output:
>
> encoder[39]
> bridge[0] type: 0, ops: 0x0
> bridge[1] type: 0, ops: 0x0, OF:
> /bus@f/i2c@2000/dsi@e:toshiba,tc358778 bridge[2] type: 0, ops: 0x3,
> OF: /bus@f/i2c@2001/hdmi@48:lontium,lt8912b bridge[3] type: 11,
> ops: 0x7, OF: /hdmi-connector:hdmi-connector
>
> Signed-off-by: Tomi Valkeinen
Looks good:
$ for dev in /sys/kernel/debug/dri/*; do cat $dev/bridge_chains; done
cat: /sys/kernel/debug/dri/0/bridge_chains: No such file or directory
encoder[36]
bridge[0] type: 0, ops: 0x0, OF: /soc@0/bus@32c0/display-
bridge@32fc4000:fsl,imx8mp-hdmi-pvi
bridge[1] type: 0, ops: 0x7, OF: /soc@0/bus@32c0/
hdmi@32fd8000:fsl,imx8mp-hdmi
cat: /sys/kernel/debug/dri/128/bridge_chains: No such file or directory
encoder[36]
bridge[0] type: 16, ops: 0x0, OF: /soc@0/bus@32c0/
dsi@32e6:fsl,imx8mp-mipi-dsim
bridge[1] type: 10, ops: 0x3, OF: /soc@0/bus@3080/i2c@30a3/
bridge@f:toshiba,tc9595
Tested-by: Alexander Stein
> ---
> Changes in v3:
> - Use drm_for_each_bridge_in_chain()
> - Drop extra comment
> - Fix whitespace issue
> - Call drm_bridge_debugfs_init() only if the driver uses modeset
> - Drop #ifdef for drm_bridge_debugfs_init() declaration
> - Link to v2:
> https://lore.kernel.org/r/20230721-drm-bridge-chain-debugfs-v2-1-76df943479
> 6...@ideasonboard.com
>
> Changes in v2:
> - Fixed compilation issue when !CONFIG_OF
> - Link to v1:
> https://lore.kernel.org/r/20230721-drm-bridge-chain-debugfs-v1-1-8614ff7e89
> 0...@ideasonboard.com ---
> drivers/gpu/drm/drm_bridge.c | 46
> +++ drivers/gpu/drm/drm_debugfs.c |
> 3 +++
> include/drm/drm_bridge.h | 3 +++
> 3 files changed, 52 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index c3d69af02e79..39e68e45bb12 100644
> --- a/drivers/gpu/drm/drm_bridge.c
> +++ b/drivers/gpu/drm/drm_bridge.c
> @@ -27,8 +27,10 @@
> #include
>
> #include
> +#include
> #include
> #include
> +#include
> #include
> #include
>
> @@ -1345,6 +1347,50 @@ struct drm_bridge *of_drm_find_bridge(struct
> device_node *np) EXPORT_SYMBOL(of_drm_find_bridge);
> #endif
>
> +#ifdef CONFIG_DEBUG_FS
> +static int drm_bridge_chains_info(struct seq_file *m, void *data)
> +{
> + struct drm_debugfs_entry *entry = m->private;
> + struct drm_device *dev = entry->dev;
> + struct drm_printer p = drm_seq_file_printer(m);
> + struct drm_mode_config *config = >mode_config;
> + struct drm_encoder *encoder;
> + unsigned int bridge_idx = 0;
> +
> + list_for_each_entry(encoder, >encoder_list, head) {
> + struct drm_bridge *bridge;
> +
> + drm_printf(, "encoder[%u]\n", encoder->base.id);
> +
> + drm_for_each_bridge_in_chain(encoder, bridge) {
> + drm_printf(, "\tbridge[%u] type: %u, ops:
%#x",
> +bridge_idx, bridge->type, bridge-
>ops);
> +
> +#ifdef CONFIG_OF
> + if (bridge->of_node)
> + drm_printf(, ", OF: %pOFfc", bridge-
>of_node);
> +#endif
> +
> + drm_printf(, "\n");
> +
> + bridge_idx++;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static const struct drm_debugfs_info drm_bridge_debugfs_list[] = {
> + { "bridge_chains", drm_bridge_chains_info, 0 },
> +};
> +
> +void drm_bridge_debugfs_init(struct drm_minor *minor)
> +{
> + drm_debugfs_add_files(minor->dev, drm_bridge_debugfs_list,
> + ARRAY_SIZE(drm_bridge_debugfs_list));
> +}
> +#endif
> +
> MODULE_AUTHOR("Ajay Kumar ");
> 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 a3a488205009..3b1de2c61c89 100644
> --- a/drivers/gpu/drm/drm_debugfs.c
> +++ b/drivers/gpu/drm/drm_debugfs.c
> @@ -31,6 +31,7 @@
>
> #include
> #include
> +#include
> #include
> #include
> #include
> @@ -274,6 +275,8 @@ int drm_debugfs_init(struct drm_minor *minor, int
> minor_id,
>
> if (drm_drv_uses_atomic_modeset(dev)) {
> drm_atomic_debugfs_init(minor);
> +
> + drm_bridge_debugfs_init(minor);
> }
>
> if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> diff
[PATCH v3] drm/bridge: Add debugfs print for bridge chains
DRM bridges are not visible to the userspace and it may not be
immediately clear if the chain is somehow constructed incorrectly. I
have had two separate instances of a bridge driver failing to do a
drm_bridge_attach() call, resulting in the bridge connector not being
part of the chain. In some situations this doesn't seem to cause issues,
but it will if DRM_BRIDGE_ATTACH_NO_CONNECTOR flag is used.
Add a debugfs file to print the bridge chains. For me, on this TI AM62
based platform, I get the following output:
encoder[39]
bridge[0] type: 0, ops: 0x0
bridge[1] type: 0, ops: 0x0, OF:
/bus@f/i2c@2000/dsi@e:toshiba,tc358778
bridge[2] type: 0, ops: 0x3, OF:
/bus@f/i2c@2001/hdmi@48:lontium,lt8912b
bridge[3] type: 11, ops: 0x7, OF: /hdmi-connector:hdmi-connector
Signed-off-by: Tomi Valkeinen
---
Changes in v3:
- Use drm_for_each_bridge_in_chain()
- Drop extra comment
- Fix whitespace issue
- Call drm_bridge_debugfs_init() only if the driver uses modeset
- Drop #ifdef for drm_bridge_debugfs_init() declaration
- Link to v2:
https://lore.kernel.org/r/20230721-drm-bridge-chain-debugfs-v2-1-76df94347...@ideasonboard.com
Changes in v2:
- Fixed compilation issue when !CONFIG_OF
- Link to v1:
https://lore.kernel.org/r/20230721-drm-bridge-chain-debugfs-v1-1-8614ff7e8...@ideasonboard.com
---
drivers/gpu/drm/drm_bridge.c | 46 +++
drivers/gpu/drm/drm_debugfs.c | 3 +++
include/drm/drm_bridge.h | 3 +++
3 files changed, 52 insertions(+)
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index c3d69af02e79..39e68e45bb12 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -27,8 +27,10 @@
#include
#include
+#include
#include
#include
+#include
#include
#include
@@ -1345,6 +1347,50 @@ struct drm_bridge *of_drm_find_bridge(struct device_node
*np)
EXPORT_SYMBOL(of_drm_find_bridge);
#endif
+#ifdef CONFIG_DEBUG_FS
+static int drm_bridge_chains_info(struct seq_file *m, void *data)
+{
+ struct drm_debugfs_entry *entry = m->private;
+ struct drm_device *dev = entry->dev;
+ struct drm_printer p = drm_seq_file_printer(m);
+ struct drm_mode_config *config = >mode_config;
+ struct drm_encoder *encoder;
+ unsigned int bridge_idx = 0;
+
+ list_for_each_entry(encoder, >encoder_list, head) {
+ struct drm_bridge *bridge;
+
+ drm_printf(, "encoder[%u]\n", encoder->base.id);
+
+ drm_for_each_bridge_in_chain(encoder, bridge) {
+ drm_printf(, "\tbridge[%u] type: %u, ops: %#x",
+ bridge_idx, bridge->type, bridge->ops);
+
+#ifdef CONFIG_OF
+ if (bridge->of_node)
+ drm_printf(, ", OF: %pOFfc", bridge->of_node);
+#endif
+
+ drm_printf(, "\n");
+
+ bridge_idx++;
+ }
+ }
+
+ return 0;
+}
+
+static const struct drm_debugfs_info drm_bridge_debugfs_list[] = {
+ { "bridge_chains", drm_bridge_chains_info, 0 },
+};
+
+void drm_bridge_debugfs_init(struct drm_minor *minor)
+{
+ drm_debugfs_add_files(minor->dev, drm_bridge_debugfs_list,
+ ARRAY_SIZE(drm_bridge_debugfs_list));
+}
+#endif
+
MODULE_AUTHOR("Ajay Kumar ");
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 a3a488205009..3b1de2c61c89 100644
--- a/drivers/gpu/drm/drm_debugfs.c
+++ b/drivers/gpu/drm/drm_debugfs.c
@@ -31,6 +31,7 @@
#include
#include
+#include
#include
#include
#include
@@ -274,6 +275,8 @@ int drm_debugfs_init(struct drm_minor *minor, int minor_id,
if (drm_drv_uses_atomic_modeset(dev)) {
drm_atomic_debugfs_init(minor);
+
+ drm_bridge_debugfs_init(minor);
}
if (drm_core_check_feature(dev, DRIVER_MODESET)) {
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index bf964cdfb330..cb10ee108538 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -949,4 +949,7 @@ static inline struct drm_bridge *drmm_of_get_bridge(struct
drm_device *drm,
}
#endif
+struct drm_minor;
+void drm_bridge_debugfs_init(struct drm_minor *minor);
+
#endif
---
base-commit: a0c64d153d687756c8719b8d10e609d62e1cb6fd
change-id: 20230721-drm-bridge-chain-debugfs-0bbc1522f57a
Best regards,
--
Tomi Valkeinen
