On czw, 2014-11-13 at 10:03 +0100, Ulf Hansson wrote: > On 13 November 2014 02:37, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: > > On Wednesday, November 12, 2014 03:32:27 PM Krzysztof Kozlowski wrote: > >> Add system suspend/resume capabilities to the pl330 driver so the amba > >> bus clock could be also unprepared to conserve energy. > >> > >> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx> > >> --- > >> drivers/dma/pl330.c | 37 +++++++++++++++++++++++++++++++++++++ > >> 1 file changed, 37 insertions(+) > >> > >> diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c > >> index c3bd3584f261..fd71777fc565 100644 > >> --- a/drivers/dma/pl330.c > >> +++ b/drivers/dma/pl330.c > >> @@ -2627,6 +2627,42 @@ static int pl330_dma_device_slave_caps(struct dma_chan *dchan, > >> return 0; > >> } > >> > >> +/* > >> + * Runtime PM callbacks are provided by amba/bus.c driver. > >> + * > >> + * It is assumed here that IRQ safe runtime PM is chosen in probe and amba > >> + * bus driver will only disable/enable the clock in runtime PM callbacks. > >> + */ > >> +static int __maybe_unused pl330_suspend(struct device *dev) > >> +{ > >> + struct amba_device *pcdev = to_amba_device(dev); > >> + > >> + if (!pm_runtime_status_suspended(dev)) { > > > > It generally isn't safe to call that in .suspend(), because the status may still > > change in theory. On the other hand, if you do that in .suspend_late(), you'll > > be safe from that. > > > > Just to clarify that statement; it's safe in a ->suspend_late() > callback, because runtime PM has been disabled by the PM core. > > That's also the reason why the pm_runtime_force_suspend() helper is > disabling runtime PM, such it may be used in some of the earlier > phases of the system PM callbacks. So actually only pm_runtime_disable() is missing here (as you mentioned earlier)? Best regards, Krzysztof -- 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