Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
drm/debugfs: show lingering bridges
The usefulness of /sys/kernel/debug/dri/bridges is limited as it only shows
bridges between drm_bridge_add() and drm_bridge_remove(). However
refcounted bridges can stay allocated and lingering for a long time after
drm_bridge_remove(), and a memory leak due to a missing drm_bridge_put()
would not be visible in this debugfs file.
Add lingering bridges to the /sys/kernel/debug/dri/bridges output.
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20250915-drm-bridge-debugfs-removed-v9-2-6e5c0aff5de9@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
+11
-5
+11
-5
drivers/gpu/drm/drm_bridge.c
+11
-5
drivers/gpu/drm/drm_bridge.c
···
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static void drm_bridge_debugfs_show_bridge(struct drm_printer *p,
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struct drm_bridge *bridge,
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-
unsigned int idx)
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+
unsigned int idx,
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+
bool lingering)
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{
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drm_printf(p, "bridge[%u]: %ps\n", idx, bridge->funcs);
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drm_printf(p, "\trefcount: %u\n", kref_read(&bridge->refcount));
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drm_printf(p, "\trefcount: %u%s\n", kref_read(&bridge->refcount),
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lingering ? " [lingering]" : "");
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drm_printf(p, "\ttype: [%d] %s\n",
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bridge->type,
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drm_get_connector_type_name(bridge->type));
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if (bridge->of_node)
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/* The OF node could be freed after drm_bridge_remove() */
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if (bridge->of_node && !lingering)
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drm_printf(p, "\tOF: %pOFfc\n", bridge->of_node);
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drm_printf(p, "\tops: [0x%x]", bridge->ops);
···
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mutex_lock(&bridge_lock);
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list_for_each_entry(bridge, &bridge_list, list)
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drm_bridge_debugfs_show_bridge(&p, bridge, idx++);
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drm_bridge_debugfs_show_bridge(&p, bridge, idx++, false);
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+
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list_for_each_entry(bridge, &bridge_lingering_list, list)
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drm_bridge_debugfs_show_bridge(&p, bridge, idx++, true);
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mutex_unlock(&bridge_lock);
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···
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unsigned int idx = 0;
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drm_for_each_bridge_in_chain_scoped(encoder, bridge)
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drm_bridge_debugfs_show_bridge(&p, bridge, idx++);
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drm_bridge_debugfs_show_bridge(&p, bridge, idx++, false);
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return 0;
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}