Re: [PATCH] drm/bridge: cdns-dsi: Fix runtime PM leak in cdns_dsi_bridge_atomic_pre_enable()

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Wed, Sep 16, 2026 at 10:04:05AM +0000, Wentao Liang wrote:
> cdns_dsi_bridge_atomic_pre_enable() resumes the DSI controller with
> pm_runtime_get_sync() and returns early with a WARN_ON() when the
> resume fails.  pm_runtime_get_sync() increments the runtime PM usage
> count even when it fails, so returning without dropping the reference
> leaks it and prevents the device from ever suspending again once the
> error has been hit.
> 
> Drop the runtime PM reference with pm_runtime_put_noidle() on the
> resume failure path before returning.
> 
> Fixes: e19233955d9e ("drm/bridge: Add Cadence DSI driver")
> Cc: stable@vger.kernel.org
> Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
> ---
>  drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
> index 0dd85e26248c..fca4528edfa6 100644
> --- a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
> +++ b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
> @@ -733,8 +733,10 @@ static void cdns_dsi_bridge_atomic_pre_enable(struct drm_bridge *bridge,
>  	 * enable their streams.
>  	 */
>  
> -	if (WARN_ON(pm_runtime_get_sync(dsi->base.dev) < 0))
> +	if (WARN_ON(pm_runtime_get_sync(dsi->base.dev) < 0)) {
> +		pm_runtime_put_noidle(dsi->base.dev);
>  		return;
> +	}

Anything wrong with pm_runtime_resume_and_get() ?

>  
>  	new_bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
>  	if (WARN_ON(!new_bridge_state))

-- 
Regards,

Laurent Pinchart