tree d4432a4fedc2b1938268531044856f34f1b87f0a
parent 0106ef5146f9e89e4dc9354f308ecaddb9617310
author Ulf Hansson <ulf.hansson@linaro.org> 1453882237 +0100
committer Rafael J. Wysocki <rafael.j.wysocki@intel.com> 1453932085 +0100

PM / Domains: Fix potential deadlock while adding/removing subdomains

We must preserve the same order of how we acquire and release the lock for
genpd, as otherwise we may encounter deadlocks.

The power on phase of a genpd starts by acquiring its lock. Then it walks
the hierarchy of its parent domains to be able to power on these first, as
per design of genpd.

From a locking perspective this means the locks of the parents becomes
acquired after the lock of the subdomain.

Let's fix pm_genpd_add|remove_subdomain() to maintain the same order of
acquiring/releasing the genpd lock as being applied in the power on/off
sequence.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>