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.boss...@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...
--
~Vinod
