Re: [PATCH 5/5] drm: release panel reference after panel bridge creation

[Albert Esteve]

On Fri, Jun 26, 2026 at 3:00 PM Maxime Ripard <mripard@xxxxxxxxxx> wrote:
>
> On Fri, Jun 26, 2026 at 02:03:27PM +0200, Albert Esteve wrote:
> > of_drm_find_panel() and drm_of_find_panel_or_bridge() now return a
> > counted reference. In drivers that immediately wrap the panel in a
> > bridge via devm_drm_panel_bridge_add() or equivalent, the bridge
> > acquires its own reference, so the caller's lookup reference must be
> > released right afterwards.
> >
> > Also handle the cases where a panel is found but cannot be used,
> > dropping the reference immediately in those paths.
> >
> > Assisted-by: Claude:claude-opus-4-6
> > Signed-off-by: Albert Esteve <aesteve@xxxxxxxxxx>
>
> drm_of_find_panel_or_bridge() does indeed return a refcounted pointer
> now, but afaik the doc wasn't updated to reflect that.

True, I'll fix that in the next version.

>
> More importantly, I feel like with both of_drm_find_panel and
> drm_of_find_panel_or_bridge we update a path that is considered legacy
> anyway now, and we should rather focus on providing a safe alternative.

Oh, I missed that this code path is considered legacy.

>
> But none of the functions you updated are unsafe, so it won't be more
> unsafe, or provide any illusion of safety to the caller. Idk.
>
> Either way, this should all be on its way out if Luca creates a bridge
> for every panel, and we'll consolidate on bridges only, so maybe it's
> not such a big deal to merge this patch.

I see. Given what you wrote, I think it'd make sense to correct them
while this code isn't completely dead.

BR,
Albert.

>
> Maxime