media: i2c: ccs-core: fix pm_runtime_get_sync() usage count

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.

Fixes: 96e3a6b92f23 ("media: smiapp: Avoid maintaining power state information")
Cc: stable@vger.kernel.org
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
index b05f409..4a848ac 100644 (file)
--- 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 previously 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(&client->dev);
+       return rval;
 }
 
 static int ccs_set_stream(struct v4l2_subdev *subdev, int enable)