On Fri, Sep 12, 2025 at 07:03:42PM +0200, Luca Ceresoli wrote:
> 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 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 removed bridges to the /sys/kernel/debug/dri/bridges output.
>
> Signed-off-by: Luca Ceresoli <luca.ceres...@bootlin.com>
>
> ---
>
> Changes in v8:
> - updated to rename bridge_removed_list -> bridge_lingering_list
>
> Changes in v7:
> - rebased on current code which is in drm_bridge.c now
> - removed if (drm_bridge_is_refcounted(bridge)), refcounting is not
> optional
> - don't show bridge address
> - improve commit message
>
> This patch was added in v6.
> ---
> drivers/gpu/drm/drm_bridge.c | 16 +++++++++++-----
> 1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index
> 9491ae7c884d355be4a82fb02a43a42d17fa8e0c..fccc42017fd4df6ecfb596325df2dc4d17566f39
> 100644
> --- a/drivers/gpu/drm/drm_bridge.c
> +++ b/drivers/gpu/drm/drm_bridge.c
> @@ -1491,17 +1491,20 @@ EXPORT_SYMBOL(devm_drm_put_bridge);
>
> static void drm_bridge_debugfs_show_bridge(struct drm_printer *p,
> struct drm_bridge *bridge,
> - unsigned int idx)
> + unsigned int idx,
> + bool removed)
> {
> drm_printf(p, "bridge[%u]: %ps\n", idx, bridge->funcs);
>
> - drm_printf(p, "\trefcount: %u\n", kref_read(&bridge->refcount));
> + drm_printf(p, "\trefcount: %u%s\n", kref_read(&bridge->refcount),
> + removed ? " [removed]" : "");I would use lingering here too, and your commit logs haven't been updated either. Maxime
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