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| author | Hans Verkuil <hverkuil@xs4all.nl> | 2018-02-21 08:49:25 +0100 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2018-03-21 17:05:39 +0100 |
| commit | 3aab15af9ad8fa8dc0399cb4b679d7cb85c20a56 (patch) | |
| tree | acd07cf67ae4ab9c752774d71a55489974359974 /drivers/media/usb/em28xx | |
| parent | media: vb2-core: vb2_ops: document non-interrupt-context calling (diff) | |
| download | linux-3aab15af9ad8fa8dc0399cb4b679d7cb85c20a56.tar.xz linux-3aab15af9ad8fa8dc0399cb4b679d7cb85c20a56.zip | |
media: add tuner standby op, use where needed
The v4l2_subdev core s_power op was used for two different things: power on/off
sensors or video decoders/encoders and to put a tuner in standby (and only the
tuner!). There is no 'tuner wakeup' op, that's done automatically when the tuner
is accessed.
The danger with calling (s_power, 0) to put a tuner into standby is that it is
usually broadcast for all subdevs. So a video receiver subdev that supports
s_power will also be powered off, and since there is no corresponding (s_power, 1)
they will never be powered on again.
In addition, this is specifically meant for tuners only since they draw the most
current.
This patch adds a new tuner op called 'standby' and replaces all calls to
(core, s_power, 0) by (tuner, standby). This prevents confusion between the two
uses of s_power. Note that there is no overlap: bridge drivers either just want
to put the tuner into standby, or they deal with powering on/off sensors. Never
both.
This also makes it easier to replace s_power for the remaining bridge drivers
with some PM code later.
Whether we want something cleaner for tuners in the future is a separate topic.
There is a lot of legacy code surrounding tuners, and I am very hesitant about
making changes there.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Diffstat (limited to 'drivers/media/usb/em28xx')
| -rw-r--r-- | drivers/media/usb/em28xx/em28xx-video.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/media/usb/em28xx/em28xx-video.c b/drivers/media/usb/em28xx/em28xx-video.c index f31339727d3b..d70ee13cc52e 100644 --- a/drivers/media/usb/em28xx/em28xx-video.c +++ b/drivers/media/usb/em28xx/em28xx-video.c @@ -2257,7 +2257,7 @@ static int em28xx_v4l2_close(struct file *filp) goto exit; /* Save some power by putting tuner to sleep */ - v4l2_device_call_all(&v4l2->v4l2_dev, 0, core, s_power, 0); + v4l2_device_call_all(&v4l2->v4l2_dev, 0, tuner, standby); /* do this before setting alternate! */ em28xx_set_mode(dev, EM28XX_SUSPEND); @@ -2810,7 +2810,7 @@ static int em28xx_v4l2_init(struct em28xx *dev) video_device_node_name(&v4l2->vbi_dev)); /* Save some power by putting tuner to sleep */ - v4l2_device_call_all(&v4l2->v4l2_dev, 0, core, s_power, 0); + v4l2_device_call_all(&v4l2->v4l2_dev, 0, tuner, standby); /* initialize videobuf2 stuff */ em28xx_vb2_setup(dev); |