Re: [PATCH] ALSA: hda: runtime PM is always active

From: Sameer Pujar
Date: Thu Jan 24 2019 - 13:15:21 EST

On 1/24/2019 9:34 PM, Takashi Iwai wrote:
On Thu, 24 Jan 2019 16:57:11 +0100,
Sameer Pujar wrote:
The runtime PM count is incremented and set to active during hda codec
device init, but it is decremented and set to suspend during exit only.
Hence the runtime PM status is always active and hda device cannot be
put to runtime suspend. Keeping device usage active for entire period,
though nothing really happening on the device, seems unnecessary.

This patch avoides incrementing runtime PM usage count of the device.

Signed-off-by: Sameer Pujar <spujar@xxxxxxxxxx>
Reviewed-by: Ravindra Lokhande <rlokhande@xxxxxxxxxx>
Reviewed-by: Mohan Kumar D <mkumard@xxxxxxxxxx>
This breaks the existing things, I'm afraid.
Did you really test and verify the behavior...?

The runtime PM refcount is decremented at snd_hda_codec_register(),
and that's the place to let runtime suspend of the codec really
effective. (It's not about the controller, though.)

It worked fine at my end. I could put the device to runtime suspend and resume it back multiple times.
Since you are suggesting it could break things, let me rework on the patch and dig up a little more to
see if there is better way to fix this.




sound/hda/hdac_device.c | 6 ------
1 file changed, 6 deletions(-)

diff --git a/sound/hda/hdac_device.c b/sound/hda/hdac_device.c
index 95b073e..72aa342 100644
--- a/sound/hda/hdac_device.c
+++ b/sound/hda/hdac_device.c
@@ -31,9 +31,6 @@ static void default_release(struct device *dev)
* Returns zero for success or a negative error code.
- * This function increments the runtime PM counter and marks it active.
- * The caller needs to turn it off appropriately later.
- *
* The caller needs to set the device's release op properly by itself.
int snd_hdac_device_init(struct hdac_device *codec, struct hdac_bus *bus,
@@ -55,8 +52,6 @@ int snd_hdac_device_init(struct hdac_device *codec, struct hdac_bus *bus,
codec->bus = bus;
codec->addr = addr;
codec->type = HDA_DEV_CORE;
- pm_runtime_set_active(&codec->dev);
- pm_runtime_get_noresume(&codec->dev);
atomic_set(&codec->in_pm, 0);
err = snd_hdac_bus_add_device(bus, codec);
@@ -123,7 +118,6 @@ EXPORT_SYMBOL_GPL(snd_hdac_device_init);
void snd_hdac_device_exit(struct hdac_device *codec)
- pm_runtime_put_noidle(&codec->dev);
snd_hdac_bus_remove_device(codec->bus, codec);