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PM / Domains: Do not measure start time for "irq safe" devices 

The genpd_start_dev() routine used by pm_genpd_runtime_resume()
to put "irq safe" devices into the full power state measures the
time necessary to "start" the device and updates its PM QoS timing
data if necessary.  This may lead to a deadlock if the given device
is a clock source and genpd_start_dev() is invoked from within the
clock source's .enable() routine, which will happen if that routine
uses pm_runtime_get_sync(), for example, to ensure that the device
is operational.

For this reason, introduce a special routine analogous to
genpd_start_dev(), called genpd_start_dev_no_timing(), that doesn't
carry out the time measurement, and make pm_genpd_runtime_resume()
use it instead of genpd_start_dev() to power up "irq safe" devices.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This commit is contained in:
Rafael J. Wysocki 2012-08-06 01:47:29 +02:00
parent dbf374142d
commit e2e3e4e51e
1 changed files with 7 additions and 1 deletions
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8
drivers/base/power/domain.c
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@ -75,6 +75,12 @@ static int genpd_start_dev(struct generic_pm_domain *genpd, struct device *dev)
start_latency_ns, "start");
}
static int genpd_start_dev_no_timing(struct generic_pm_domain *genpd,
struct device *dev)
{
return GENPD_DEV_CALLBACK(genpd, int, start, dev);
}
static bool genpd_sd_counter_dec(struct generic_pm_domain *genpd)
{
bool ret = false;
@ -626,7 +632,7 @@ static int pm_genpd_runtime_resume(struct device *dev)
/* If power.irq_safe, the PM domain is never powered off. */
if (dev->power.irq_safe)
return genpd_start_dev(genpd, dev);
return genpd_start_dev_no_timing(genpd, dev);
mutex_lock(&genpd->lock);
ret = __pm_genpd_poweron(genpd);