On Monday, September 25, 2017 9:12:28 PM CEST Ulf Hansson wrote: > On 25 September 2017 at 01:17, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: > > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > > > The power management handling in dw_i2c_plat_probe() is somewhat > > messy and it is rather hard to figure out the code intention for > > the case when pm_disabled is set. In that case, the driver doesn't > > enable runtime PM at all, but in addition to that it calls > > pm_runtime_forbid() as though it wasn't sure if runtime PM might > > be enabled for the device later by someone else. > > > > Although that concern doesn't seem to be actually valid, the > > device is clearly still expected to be PM-capable even in the > > pm_disabled set case, so a better approach would be to enable > > runtime PM for it unconditionally and then prevent it from > > being runtime-suspended by using pm_runtime_forbid(). > > This is nice cleanup! However I have one suggestion/comment. > > Using pm_runtime_forbid() to prevent the device from being runtime > suspended may be a bit fragile, as userspace can then still change to > "allow" it. Wouldn't it be better to bump the runtime PM usage count > (pm_runtime_get_noresume()) instead? Right, this is not a PCI driver. :-) I'll send an update of this patch shortly. Thanks, Rafael
