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  1. 15 7月, 2011 1 次提交
  3. 13 7月, 2011 2 次提交
  5. 12 7月, 2011 7 次提交
    • R
      PM / Domains: Queue up power off work only if it is not pending · 56375fd4
      由 Rafael J. Wysocki 提交于 
      In theory it is possible that pm_genpd_poweroff() for two different
subdomains of the same parent domain will attempt to queue up the
execution of pm_genpd_poweroff() for the parent twice in a row.  This
would lead to unpleasant consequences, so prevent it from happening
by checking if genpd->power_off_work is pending before attempting to
queue it up.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
      56375fd4
    • R
      PM / Domains: Improve handling of wakeup devices during system suspend · 4ecd6e65
      由 Rafael J. Wysocki 提交于 
      Kevin points out that if there's a device that can wake up the system
from sleep states, but it doesn't generate wakeup signals by itself
(they are generated on its behalf by other parts of the system) and
it currently is not enabled to wake up the system (that is,
device_may_wakeup() returns "false" for it), we may need to change
its wakeup settings during system suspend (for example, the device
might have been configured to signal remote wakeup from the system's
working state, as needed by runtime PM).  Therefore the generic PM
domains code should invoke the system suspend callbacks provided by
the device's driver, which it doesn't do if the PM domain is powered
off during the system suspend's "prepare" stage.  This is a valid
point.  Moreover, this code also should make sure that system wakeup
devices that are enabled to wake up the system from sleep states and
have to remain active for this purpose are not suspended while the
system is in a sleep state.

To avoid the above issues, make the generic PM domains' .prepare()
routine, pm_genpd_prepare(), force runtime resume of devices whose
system wakeup settings may need to be changed during system suspend
or that should remain active while the system is in a sleep state to
be able to wake it up from that state.
Reported-by: NKevin Hilman <khilman@ti.com>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
      4ecd6e65
    • R
      PM / Domains: Do not restore all devices on power off error · 697a7f37
      由 Rafael J. Wysocki 提交于 
      Since every device in a PM domain has its own need_restore
flag, which is set by __pm_genpd_save_device(), there's no need to
walk the domain's device list and restore all devices on an error
from one of the drivers' .runtime_suspend() callbacks.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
      697a7f37
    • R
      PM / Domains: Allow callbacks to execute all runtime PM helpers · c6d22b37
      由 Rafael J. Wysocki 提交于 
      A deadlock may occur if one of the PM domains' .start_device() or
.stop_device() callbacks or a device driver's .runtime_suspend() or
.runtime_resume() callback executed by the core generic PM domain
code uses a "wrong" runtime PM helper function.  This happens, for
example, if .runtime_resume() from one device's driver calls
pm_runtime_resume() for another device in the same PM domain.
A similar situation may take place if a device's parent is in the
same PM domain, in which case the runtime PM framework may execute
pm_genpd_runtime_resume() automatically for the parent (if it is
suspended at the moment).  This, of course, is undesirable, so
the generic PM domains code should be modified to prevent it from
happening.

The runtime PM framework guarantees that pm_genpd_runtime_suspend()
and pm_genpd_runtime_resume() won't be executed in parallel for
the same device, so the generic PM domains code need not worry
about those cases.  Still, it needs to prevent the other possible
race conditions between pm_genpd_runtime_suspend(),
pm_genpd_runtime_resume(), pm_genpd_poweron() and pm_genpd_poweroff()
from happening and it needs to avoid deadlocks at the same time.
To this end, modify the generic PM domains code to relax
synchronization rules so that:

* pm_genpd_poweron() doesn't wait for the PM domain status to
  change from GPD_STATE_BUSY.  If it finds that the status is
  not GPD_STATE_POWER_OFF, it returns without powering the domain on
  (it may modify the status depending on the circumstances).

* pm_genpd_poweroff() returns as soon as it finds that the PM
  domain's status changed from GPD_STATE_BUSY after it's released
  the PM domain's lock.

* pm_genpd_runtime_suspend() doesn't wait for the PM domain status
  to change from GPD_STATE_BUSY after executing the domain's
  .stop_device() callback and executes pm_genpd_poweroff() only
  if pm_genpd_runtime_resume() is not executed in parallel.

* pm_genpd_runtime_resume() doesn't wait for the PM domain status
  to change from GPD_STATE_BUSY after executing pm_genpd_poweron()
  and sets the domain's status to GPD_STATE_BUSY and increments its
  counter of resuming devices (introduced by this change) immediately
  after acquiring the lock.  The counter of resuming devices is then
  decremented after executing __pm_genpd_runtime_resume() for the
  device and the domain's status is reset to GPD_STATE_ACTIVE (unless
  there are more resuming devices in the domain, in which case the
  status remains GPD_STATE_BUSY).

This way, for example, if a device driver's .runtime_resume()
callback executes pm_runtime_resume() for another device in the same
PM domain, pm_genpd_poweron() called by pm_genpd_runtime_resume()
invoked by the runtime PM framework will not block and it will see
that there's nothing to do for it.  Next, the PM domain's lock will
be acquired without waiting for its status to change from
GPD_STATE_BUSY and the device driver's .runtime_resume() callback
will be executed.  In turn, if pm_runtime_suspend() is executed by
one device driver's .runtime_resume() callback for another device in
the same PM domain, pm_genpd_poweroff() executed by
pm_genpd_runtime_suspend() invoked by the runtime PM framework as a
result will notice that one of the devices in the domain is being
resumed, so it will return immediately.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
      c6d22b37
    • R
      PM / Domains: Do not execute device callbacks under locks · 17b75eca
      由 Rafael J. Wysocki 提交于 
      Currently, the .start_device() and .stop_device() callbacks from
struct generic_pm_domain() as well as the device drivers' runtime PM
callbacks used by the generic PM domains code are executed under
the generic PM domain lock.  This, unfortunately, is prone to
deadlocks, for example if a device and its parent are boths members
of the same PM domain.  For this reason, it would be better if the
PM domains code didn't execute device callbacks under the lock.

Rework the locking in the generic PM domains code so that the lock
is dropped for the execution of device callbacks.  To this end,
introduce PM domains states reflecting the current status of a PM
domain and such that the PM domain lock cannot be acquired if the
status is GPD_STATE_BUSY.  Make threads attempting to acquire a PM
domain's lock wait until the status changes to either
GPD_STATE_ACTIVE or GPD_STATE_POWER_OFF.

This change by itself doesn't fix the deadlock problem mentioned
above, but the mechanism introduced by it will be used for for this
purpose by a subsequent patch.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
      17b75eca
    • R
      PM / Domains: Make failing pm_genpd_prepare() clean up properly · b6c10c84
      由 Rafael J. Wysocki 提交于 
      If pm_generic_prepare() in pm_genpd_prepare() returns error code,
the PM domains counter of "prepared" devices should be decremented
and its suspend_power_off flag should be reset if this counter drops
down to zero.  Otherwise, the PM domain runtime PM code will not
handle the domain correctly (it will permanently think that system
suspend is in progress).
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
      b6c10c84
    • R
      PM / Domains: Set device state to "active" during system resume · 6f00ff78
      由 Rafael J. Wysocki 提交于 
      The runtime PM status of devices in a power domain that is not
powered off in pm_genpd_complete() should be set to "active", because
those devices are operational at this point.  Some of them may not be
in use, though, so make pm_genpd_complete() call pm_runtime_idle()
in addition to pm_runtime_set_active() for each of them.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
      6f00ff78
  7. 10 7月, 2011 7 次提交
  9. 02 7月, 2011 20 次提交
  11. 01 7月, 2011 3 次提交