Hi Mauro,
Thanks for the patch.
On Wed, May 05, 2021 at 11:42:15AM +0200, Mauro Carvalho Chehab wrote:
> The pm_runtime_get_sync() internally increments the
> dev->power.usage_count without decrementing it, even on errors.
>
> There is a bug at ccs_pm_get_init(): when this function returns
> an error, the stream is not started, and RPM usage_count
> should not be incremented. However, if the calls to
> v4l2_ctrl_handler_setup() return errors, it will be kept
> incremented.
>
> At ccs_suspend() the best is to 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 automatically,
> in the case of errors.
>
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
Could you add Fixes: line and Cc: stable?
The patch that breaks this is 96e3a6b92f23a .
It would be better to fix the bug first so the patch to the stable trees
doesn't need special handling.
> ---
> drivers/media/i2c/ccs/ccs-core.c | 39 ++++++++++++++++++++------------
> 1 file changed, 24 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
> index b05f409014b2..04c3ab9e37b4 100644
> --- a/drivers/media/i2c/ccs/ccs-core.c
> +++ b/drivers/media/i2c/ccs/ccs-core.c
> @@ -1880,21 +1880,33 @@ static int ccs_pm_get_init(struct ccs_sensor *sensor)
> struct i2c_client *client = v4l2_get_subdevdata(&sensor->src->sd);
> int rval;
>
> + /*
> + * It can't use pm_runtime_resume_and_get() here, as the driver
> + * relies at the returned value to detect if the device was already
> + * active or not.
> + */
> rval = pm_runtime_get_sync(&client->dev);
> - if (rval < 0) {
> - pm_runtime_put_noidle(&client->dev);
> + if (rval < 0)
> + goto error;
>
> - return rval;
> - } else if (!rval) {
> - rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->
> - ctrl_handler);
> - if (rval)
> - return rval;
> + /* Device was already active, so don't set controls */
> + if (rval == 1)
> + return 0;
>
> - return v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> - }
> + /* Restore V4L2 controls to the suspended device */
> + rval = v4l2_ctrl_handler_setup(&sensor->pixel_array->ctrl_handler);
> + if (rval)
> + goto error;
>
> + rval = v4l2_ctrl_handler_setup(&sensor->src->ctrl_handler);
> + if (rval)
> + goto error;
> +
> + /* Keep PM runtime usage_count incremented on success */
> return 0;
> +error:
> + pm_runtime_put_noidle(&client->dev);
This needs to be pm_runtime_put() as the device has been successfully.
> + return rval;
> }
>
> static int ccs_set_stream(struct v4l2_subdev *subdev, int enable)
> @@ -3089,12 +3101,9 @@ static int __maybe_unused ccs_suspend(struct device *dev)
> bool streaming = sensor->streaming;
> int rval;
>
> - rval = pm_runtime_get_sync(dev);
> - if (rval < 0) {
> - pm_runtime_put_noidle(dev);
> -
> + rval = pm_runtime_resume_and_get(dev);
> + if (rval < 0)
> return rval;
> - }
>
> if (sensor->streaming)
> ccs_stop_streaming(sensor);
--
Kind regards,
Sakari Ailus
