Mikko Perttunen 5ad064a2bb drm/tegra: Enable runtime PM during probe for internal engines ...

Currently, engine drivers only enable runtime PM during the host1x
init callback. This can happen slightly later than the probe, which
can cause the power domain to intermittently not be turned off after
probe.

My hypothesis is that there is a race condition between the post-probe
power domain poweroff that is done from a queued work, and the
pm_runtime_enable call happening in the host1x init callback.
If the pm_runtime_enable call happens first, everything is OK and
the power off work can disable the power domain as PM runtime is
enabled and the device is runtime suspended. If power off work runs
first, PM runtime is still disabled for the device and the domain
must be kept powered.

Resolve the issue by moving the runtime PM enablement to the
probe function.

Bug 3982357

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Change-Id: I9a10e1dff580affebe05d9cc9ab3e24d1d3ca547
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvidia/+/2859476
Reviewed-by: Santosh BS <santoshb@nvidia.com>
GVS: Gerrit_Virtual_Submit <buildbot_gerritrpt@nvidia.com>

2023-04-03 09:18:59 +00:00

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