releases/4.19.34/media-ov7740-fix-runtime-pm-initialization.patch

   1 From ca6cf64a68b93bef63167ef8692efedcc1d6769c Mon Sep 17 00:00:00 2001
   2 From: Akinobu Mita <akinobu.mita@gmail.com>
   3 Date: Sun, 17 Feb 2019 10:17:47 -0500
   4 Subject: media: ov7740: fix runtime pm initialization
   5
   6 [ Upstream commit 12aceee1f412c3ddc7750155fec06c906f14ab51 ]
   7
   8 The runtime PM of this device is enabled after v4l2_ctrl_handler_setup(),
   9 and this makes this device's runtime PM usage count a negative value.
  10
  11 The ov7740_set_ctrl() tries to do something only if the device's runtime
  12 PM usage counter is nonzero.
  13
  14 ov7740_set_ctrl()
  15 {
  16         if (!pm_runtime_get_if_in_use(&client->dev))
  17                 return 0;
  18
  19         <do something>;
  20
  21         pm_runtime_put(&client->dev);
  22
  23         return ret;
  24 }
  25
  26 However, the ov7740_set_ctrl() is called by v4l2_ctrl_handler_setup()
  27 while the runtime PM of this device is not yet enabled.  In this case,
  28 the pm_runtime_get_if_in_use() returns -EINVAL (!= 0).
  29
  30 Therefore we can't bail out of this function and the usage count is
  31 decreased by pm_runtime_put() without increment.
  32
  33 This fixes this problem by enabling the runtime PM of this device before
  34 v4l2_ctrl_handler_setup() so that the ov7740_set_ctrl() is always called
  35 when the runtime PM is enabled.
  36
  37 Cc: Wenyou Yang <wenyou.yang@microchip.com>
  38 Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
  39 Tested-by: Eugen Hristev <eugen.hristev@microchip.com>
  40 Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
  41 Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
  42 Signed-off-by: Sasha Levin <sashal@kernel.org>
  43 ---
  44  drivers/media/i2c/ov7740.c | 7 +++++--
  45  1 file changed, 5 insertions(+), 2 deletions(-)
  46
  47 diff --git a/drivers/media/i2c/ov7740.c b/drivers/media/i2c/ov7740.c
  48 index 605f3e25ad82..f5a1ee90a6c5 100644
  49 --- a/drivers/media/i2c/ov7740.c
  50 +++ b/drivers/media/i2c/ov7740.c
  51 @@ -1101,6 +1101,9 @@ static int ov7740_probe(struct i2c_client *client,
  52         if (ret)
  53                 return ret;
  54
  55 +       pm_runtime_set_active(&client->dev);
  56 +       pm_runtime_enable(&client->dev);
  57 +
  58         ret = ov7740_detect(ov7740);
  59         if (ret)
  60                 goto error_detect;
  61 @@ -1123,8 +1126,6 @@ static int ov7740_probe(struct i2c_client *client,
  62         if (ret)
  63                 goto error_async_register;
  64
  65 -       pm_runtime_set_active(&client->dev);
  66 -       pm_runtime_enable(&client->dev);
  67         pm_runtime_idle(&client->dev);
  68
  69         return 0;
  70 @@ -1134,6 +1135,8 @@ error_async_register:
  71  error_init_controls:
  72         ov7740_free_controls(ov7740);
  73  error_detect:
  74 +       pm_runtime_disable(&client->dev);
  75 +       pm_runtime_set_suspended(&client->dev);
  76         ov7740_set_power(ov7740, 0);
  77         media_entity_cleanup(&ov7740->subdev.entity);
  78
  79 --
  80 2.19.1
  81