On 08-04-19, 12:43, Pierre-Louis Bossart wrote:
On 4/8/19 2:12 AM, Jan Kotas wrote:
On 5 Apr 2019, at 17:04, Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com wrote:
On 4/5/19 2:26 AM, Jan Kotas wrote:
ret = pm_runtime_get_sync(slave->bus->dev);
- if (ret < 0)
- if (ret < 0 && ret != -EACCES)
There was a patch submitted on 3/28 by Srinivas Kandagatla who suggested an alternate solution for exactly the same code.
- if (pm_runtime_enabled(slave->bus->dev)) {
ret = pm_runtime_get_sync(slave->bus->dev);if (ret < 0)return ret;I am far from an expert on pm_runtime but Srinivas' solution looks more elegant to me.
Hello Pierre,
Please take a look at this patch, that was my inspiration: https://lists.linuxfoundation.org/pipermail/linux-pm/2011-June/031930.html
The two patches seems to be identical:
static inline bool pm_runtime_enabled(struct device *dev) { return !dev->power.disable_depth; }
static int rpm_resume() [...] else if (dev->power.disable_depth > 0) retval = -EACCES;
However I am still not clear on why this might fail.
I can only think of one possible explanation: there is no explicit pm_runtime_enable() in the soundwire code, so maybe the expectation is that the pm_runtime status is inherited from the parent (in the intel case the PCI driver), and that's missing in non-intel configurations?
IIRC that needs to be called by the Intel driver and those patches were not upstreamed. So we dont have fully supported PM on upstream yet!
I also took a look, and it seems the value returned by pm_runtime_get_syncis simply ignored in a lot of places, so checking its value may be excessive.
But not checking seems careless at best...