dev->power.is_suspended is set after core suspends device during system suspend. This flag mostly means device is not operational (all I/O been quiesced, no more data read or write acceptible, etc.), hence it's dangerous to access hardware if device is suspended even though runtime PM status is RPM_ACTIVE.
In turn, we should allow device to be accessed in case device is *not* suspended and runtime PM status is RPM_ACTIVE, even if runtime PM disabled. This corner case can happen to a device in a generic PM domain if the domain is not powered off while preparing for a system-wide power transition. In this case, runtime PM status will be set to RPM_ACTIVE and then runtime PM is disabled. After that, device driver may call pm_runtime_get_sync() and rpm_resume() should return 1, because the device is still active as long as not been suspended. Signed-off-by: Allen Yu <[email protected]> --- drivers/base/power/runtime.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 67c7938..39885f1 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -608,7 +608,7 @@ static int rpm_resume(struct device *dev, int rpmflags) repeat: if (dev->power.runtime_error) retval = -EINVAL; - else if (dev->power.disable_depth == 1 && dev->power.is_suspended + else if (dev->power.disable_depth == 1 && !dev->power.is_suspended && dev->power.runtime_status == RPM_ACTIVE) retval = 1; else if (dev->power.disable_depth > 0) -- 1.8.1.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
