On Fri, Jul 26, 2019 at 01:08:57PM -0500, Pierre-Louis Bossart wrote:
This thread became unreadable with interleaved top-posting, allow me restate the options and ask PM folks what they think
On 7/25/19 6:40 PM, 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);This is option1: we explicitly test if pm_runtime is enabled before calling _get_sync() and _put()
option2 (suggested by Jan Kotas): catch the -EACCESS error code
ret = pm_runtime_get_sync(slave->bus->dev);
- if (ret < 0)
- if (ret < 0 && ret != -EACCES) return ret;
option3: ignore the return value as done in quite a few drivers
Are there any other options? I am personally surprised this is not handled in the pm_runtime core, not sure why users need to test for this?
option 4: fix this in runtime PM :-) This seems like the best option to me, but probably not the easiest one. Otherwise I'd go with (2), I think, since that's also the official purpose of the -EACCESS return code:
https://lists.linuxfoundation.org/pipermail/linux-pm/2011-June/031930.html
Thanks Guennadi