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12aceee1f4
The runtime PM of this device is enabled after v4l2_ctrl_handler_setup(),
and this makes this device's runtime PM usage count a negative value.
The ov7740_set_ctrl() tries to do something only if the device's runtime
PM usage counter is nonzero.
ov7740_set_ctrl()
{
if (!pm_runtime_get_if_in_use(&client->dev))
return 0;
<do something>;
pm_runtime_put(&client->dev);
return ret;
}
However, the ov7740_set_ctrl() is called by v4l2_ctrl_handler_setup()
while the runtime PM of this device is not yet enabled. In this case,
the pm_runtime_get_if_in_use() returns -EINVAL (!= 0).
Therefore we can't bail out of this function and the usage count is
decreased by pm_runtime_put() without increment.
This fixes this problem by enabling the runtime PM of this device before
v4l2_ctrl_handler_setup() so that the ov7740_set_ctrl() is always called
when the runtime PM is enabled.
Cc: Wenyou Yang <wenyou.yang@microchip.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Tested-by: Eugen Hristev <eugen.hristev@microchip.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.