On Wed, Sep 24, 2014 at 03:47:17PM -0400, Alan Stern wrote: > On Wed, 24 Sep 2014, Pavel Machek wrote: > > > On Wed 2014-09-24 15:50:08, Krzysztof Kozlowski wrote: > > > Add a simple getter pm_runtime_is_irq_safe() for quering whether runtime > > > PM IRQ safe was set or not. > > > > > > Various bus drivers implementing runtime PM may use choose to suspend > > > differently based on IRQ safeness status of child driver (e.g. do not > > > unprepare the clock if IRQ safe is not set). > > > > > > Signed-off-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx> > > > Reviewed-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> > > > > Are you sure this is good interface? > > > > "Tell me if another function works this or that way". > > > > That's certainly not traditional interface, and it seems dangerous to > > me. Callbacks now have different semantic requirements based on value > > of some flag... > > > > Would it be possible to have two sets of callbacks, one irq safe and > > one not? > > Or maybe add a flag to the bus-specific device structures, indicating > specifically whether or not the clock should be unprepared during a > runtime suspend. Then individual drivers could set this flag or not, > independent of the irq-safe setting. What you're proposing is _less_ safe, because with your proposal, you now have the possibility that drivers will tell runtime PM that it has IRQ safe callbacks, but the bus code tries to prepare/unprepare the clock, which causes a might-sleep-if warning. This is fragile. -- FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
