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/openbmc/linux/drivers/base/power/
H A Ddomain.ce2e3e4e5 Sun Aug 05 18:47:29 CDT 2012 Rafael J. Wysocki <rjw@sisk.pl> 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>
e2e3e4e5 Sun Aug 05 18:47:29 CDT 2012 Rafael J. Wysocki <rjw@sisk.pl> 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>