On Wed, 5 May 2021 11:42:12 +0200
Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> wrote:
> The pm_runtime_get_sync() internally increments the
> dev->power.usage_count without decrementing it, even on errors.
>
> The bdisp_start_streaming() doesn't take it into account, which
> would unbalance PM usage counter at bdisp_stop_streaming().
>
> The logic at bdisp_probe() is correct, but the best is to use
> the same call along the driver.
>
> So, replace it by the new pm_runtime_resume_and_get(), introduced by:
> commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter")
> in order to properly decrement the usage counter, avoiding
> a potential PM usage counter leak.
>
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> ---
> drivers/media/platform/sti/bdisp/bdisp-v4l2.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/media/platform/sti/bdisp/bdisp-v4l2.c b/drivers/media/platform/sti/bdisp/bdisp-v4l2.c
> index 060ca85f64d5..85288da9d2ae 100644
> --- a/drivers/media/platform/sti/bdisp/bdisp-v4l2.c
> +++ b/drivers/media/platform/sti/bdisp/bdisp-v4l2.c
> @@ -499,7 +499,7 @@ static int bdisp_start_streaming(struct vb2_queue *q, unsigned int count)
> {
> struct bdisp_ctx *ctx = q->drv_priv;
> struct vb2_v4l2_buffer *buf;
> - int ret = pm_runtime_get_sync(ctx->bdisp_dev->dev);
> + int ret = pm_runtime_resume_and_get(ctx->bdisp_dev->dev);
>
> if (ret < 0) {
> dev_err(ctx->bdisp_dev->dev, "failed to set runtime PM\n");
> @@ -1364,10 +1364,10 @@ static int bdisp_probe(struct platform_device *pdev)
>
> /* Power management */
> pm_runtime_enable(dev);
> - ret = pm_runtime_get_sync(dev);
> + ret = pm_runtime_resume_and_get(dev);
> if (ret < 0) {
> dev_err(dev, "failed to set PM\n");
> - goto err_pm;
> + goto err_remove;
> }
>
> /* Filters */
> @@ -1395,6 +1395,7 @@ static int bdisp_probe(struct platform_device *pdev)
> bdisp_hw_free_filters(bdisp->dev);
> err_pm:
> pm_runtime_put(dev);
> +err_remove:
> bdisp_debugfs_remove(bdisp);
> v4l2_device_unregister(&bdisp->v4l2_dev);
> err_clk:
