[PATCH 2/4] drm/panel/samsung-dsicm: Keep up with refcounting

[Maxime Ripard]

On Mon, Jun 09, 2025 at 10:45:35AM -0500, Anusha Srivatsa wrote:
> On Fri, Jun 6, 2025 at 7:03 AM Maxime Ripard <mripard at kernel.org> wrote:
> 
> > On Wed, Jun 04, 2025 at 10:45:11PM -0500, Anusha Srivatsa wrote:
> > > Put the panel reference back when driver is no
> > > longer using it.
> > >
> > > Signed-off-by: Anusha Srivatsa <asrivats at redhat.com>
> > > ---
> > >  drivers/gpu/drm/bridge/samsung-dsim.c | 1 +
> > >  1 file changed, 1 insertion(+)
> > >
> > > diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
> > b/drivers/gpu/drm/bridge/samsung-dsim.c
> > > index
> > 0014c497e3fe7d8349a119dbdda30d65d816cccf..3667855ff0d6d1b608c579573de657af7fd14388
> > 100644
> > > --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> > > +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> > > @@ -1748,6 +1748,7 @@ static int samsung_dsim_host_attach(struct
> > mipi_dsi_host *host,
> > >                       dsi->out_bridge = ERR_PTR(-EINVAL);
> > >       }
> > >
> > > +     drm_panel_put(panel);
> > >       of_node_put(remote);
> > >
> > >       if (IS_ERR(dsi->out_bridge)) {
> >
> > Explaining in your commit log why you think it's a good idea to put it
> > there would be really nice. In particular, it looks super odd to me that
> > you would put the panel reference in attach.
> >
> > Also, your patch doesn't work, and you have a reference inbalance. You
> > have one taken by the panel driver, put in remove. You have one in
> > drm_panel_add, put in drm_panel_remove. Which reference do you put here?
> >
> > This applies to your other patches too.
>
> Yes, I should get the ref in of_drm_find_panel() to put it here. With
> that said, all callers of of_drm_find_panel() should be converted
> instead of the small batch that this series addresses.

Then do the of_drm_find_panel() conversion before, because here you will
free up the structure despite some callers still having a reference on
it.

Maxime
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