From 8e4bb53c902ed2b06a2c4778e6dbb2c1eeec4960 Mon Sep 17 00:00:00 2001 From: Tomi Valkeinen Date: Wed, 2 Aug 2023 10:04:11 +0300 Subject: [PATCH] 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@f0000/i2c@20000000/dsi@e:toshiba,tc358778 bridge[2] type: 0, ops: 0x3, OF: /bus@f0000/i2c@20010000/hdmi@48:lontium,lt8912b bridge[3] type: 11, ops: 0x7, OF: /hdmi-connector:hdmi-connector Tested-by: Alexander Stein Reviewed-by: Laurent Pinchart Signed-off-by: Tomi Valkeinen Acked-by: Neil Armstrong Signed-off-by: Neil Armstrong Link: https://patchwork.freedesktop.org/patch/msgid/20230802-drm-bridge-chain-debugfs-v4-1-7e3ae3d137c0@ideasonboard.com --- drivers/gpu/drm/drm_bridge.c | 46 +++++++++++++++++++++++++++++++++++++++++++ drivers/gpu/drm/drm_debugfs.c | 2 ++ include/drm/drm_bridge.h | 3 +++ 3 files changed, 51 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 = &dev->mode_config; + struct drm_encoder *encoder; + unsigned int bridge_idx = 0; + + list_for_each_entry(encoder, &config->encoder_list, head) { + struct drm_bridge *bridge; + + drm_printf(&p, "encoder[%u]\n", encoder->base.id); + + drm_for_each_bridge_in_chain(encoder, bridge) { + drm_printf(&p, "\tbridge[%u] type: %u, ops: %#x", + bridge_idx, bridge->type, bridge->ops); + +#ifdef CONFIG_OF + if (bridge->of_node) + drm_printf(&p, ", OF: %pOFfc", bridge->of_node); +#endif + + drm_printf(&p, "\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..2de43ff3ce0a 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 +275,7 @@ 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..c339fc85fd07 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -36,6 +36,7 @@ struct drm_bridge; struct drm_bridge_timings; struct drm_connector; struct drm_display_info; +struct drm_minor; struct drm_panel; struct edid; struct i2c_adapter; @@ -949,4 +950,6 @@ static inline struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm, } #endif +void drm_bridge_debugfs_init(struct drm_minor *minor); + #endif -- 2.11.0