[PATCH] drm:bridge:analogix: Fix refcount bugs in anx7625_parse_dt()

[Robert Foss]

Hey Liang,


On Thu, 7 Jul 2022 at 03:25, Liang He <windhl at 126.com> wrote:
>
> There are two refcount bugs in this funcion:
>
> BUG-1: 'pdata->mipi_host_node' will be assigned a new reference with
> of_graph_get_remote_node() which will increase the refcount of the
> object, correspondingly, we should call of_node_put() for the old
> reference stored in the 'pdata->mipi_host_node'.
>
> BUG-2: of_graph_get_endpoint_by_regs() will also increase the refcount
> of the object and its new reference will be assigned to local 'ep0', so
> there should be a of_node_put() when 'ep0' is not used anymore.
>
> Fixes: 8bdfc5dae4e3 ("drm/bridge: anx7625: Add anx7625 MIPI DSI/DPI to DP")
> Fixes: fd0310b6fe7d ("drm/bridge: anx7625: add MIPI DPI input feature")
> Signed-off-by: Liang He <windhl at 126.com>
> ---
>  drivers/gpu/drm/bridge/analogix/anx7625.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> index 53a5da6c49dd..f39b9be19eaf 100644
> --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> @@ -1624,6 +1624,7 @@ static int anx7625_parse_dt(struct device *dev,
>         anx7625_get_swing_setting(dev, pdata);
>
>         pdata->is_dpi = 1; /* default dpi mode */
> +       of_node_put(pdata->mipi_host_node);
>         pdata->mipi_host_node = of_graph_get_remote_node(np, 0, 0);
>         if (!pdata->mipi_host_node) {
>                 DRM_DEV_ERROR(dev, "fail to get internal panel.\n");
> @@ -1638,6 +1639,7 @@ static int anx7625_parse_dt(struct device *dev,
>                         bus_type = 0;
>
>                 mipi_lanes = of_property_count_u32_elems(ep0, "data-lanes");
> +               of_node_put(ep0);
>         }
>
>         if (bus_type == V4L2_FWNODE_BUS_TYPE_PARALLEL) /* bus type is Parallel(DSI) */
> --
> 2.25.1
>

This patch does not apply on drm-misc-next, could you please rebase it
and send a v2?

Rob.