28.04.2020 07:20, Sowjanya Komatineni пишет:
> diff --git a/drivers/staging/media/tegra-video/csi.c
> b/drivers/staging/media/tegra-video/csi.c
> index b3dd0c3..29ccdae 100644
> --- a/drivers/staging/media/tegra-video/csi.c
> +++ b/drivers/staging/media/tegra-video/csi.c
> @@ -272,8 +272,25 @@ static int tegra_csi_s_stream(struct v4l2_subdev
> *subdev, int enable)
> struct tegra_vi_channel *chan = v4l2_get_subdev_hostdata(subdev);
> struct tegra_csi_channel *csi_chan = to_csi_chan(subdev);
> struct tegra_csi *csi = csi_chan->csi;
> + int ret;
> +
> + if (enable && atomic_add_return(1, &csi->clk_refcnt) == 1) {
> + ret = pm_runtime_get_sync(csi->dev);
> + if (ret < 0) {
> + dev_err(csi->dev,
> + "failed to get runtime PM: %d\n", ret);
> + pm_runtime_put_noidle(csi->dev);
> + atomic_dec(&csi->clk_refcnt);
> + return ret;
> + }
> + }
> +
> + ret = csi->ops->csi_streaming(csi_chan, chan->pg_mode, enable);
>
> - return csi->ops->csi_streaming(csi_chan, chan->pg_mode, enable);
> + if ((ret < 0 || !enable) && atomic_dec_and_test(&csi->clk_refcnt))
> + pm_runtime_put_sync(csi->dev);
Runtime PM maintains its own refcount, why these
clk_refcnt/power_on_refcnt are needed?
