Re: [alsa-devel] [RFC PATCH 17/40] soundwire: bus: use runtime_pm_get_sync/pm when enabled

Guennadi Liakhovetski
2019-07-26T07:39:38Z

Hi Pierre,

I might be wrong but this doesn't seem right to me. (Supposedly) all RT-PM
functions check for "enabled" internally. The only thing that can happen is
that if RT-PM isn't enabled some of those functions will return an error.
So, in those cases where the return value of RT-PM functions isn't checked,
I don't think you need to do anything. Where it is checked maybe do

+ if (ret < 0 && pm_runtime_enabled(slave->bus->dev))

Thanks
Guennadi

On Thu, Jul 25, 2019 at 06:40:09PM -0500, Pierre-Louis Bossart wrote:
> Not all platforms support runtime_pm for now, let's use runtime_pm
> only when enabled.
>
> Suggested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> ---
> drivers/soundwire/bus.c | 25 ++++++++++++++++---------
> 1 file changed, 16 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
> index 5ad4109dc72f..0a45dc5713df 100644
> --- a/drivers/soundwire/bus.c
> +++ b/drivers/soundwire/bus.c
> @@ -332,12 +332,16 @@ int sdw_nread(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
> if (ret < 0)
> return ret;
>
> - ret = pm_runtime_get_sync(slave->bus->dev);
> - if (ret < 0)
> - return ret;
> + if (pm_runtime_enabled(slave->bus->dev)) {
> + ret = pm_runtime_get_sync(slave->bus->dev);
> + if (ret < 0)
> + return ret;
> + }
>
> ret = sdw_transfer(slave->bus, &msg);
> - pm_runtime_put(slave->bus->dev);
> +
> + if (pm_runtime_enabled(slave->bus->dev))
> + pm_runtime_put(slave->bus->dev);
>
> return ret;
> }
> @@ -359,13 +363,16 @@ int sdw_nwrite(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
> slave->dev_num, SDW_MSG_FLAG_WRITE, val);
> if (ret < 0)
> return ret;
> -
> - ret = pm_runtime_get_sync(slave->bus->dev);
> - if (ret < 0)
> - return ret;
> + if (pm_runtime_enabled(slave->bus->dev)) {
> + ret = pm_runtime_get_sync(slave->bus->dev);
> + if (ret < 0)
> + return ret;
> + }
>
> ret = sdw_transfer(slave->bus, &msg);
> - pm_runtime_put(slave->bus->dev);
> +
> + if (pm_runtime_enabled(slave->bus->dev))
> + pm_runtime_put(slave->bus->dev);
>
> return ret;
> }
> --
> 2.20.1
>
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