tree b76404165493a2f749f1ac7aad0c792797e422b3
parent dd0b0e22a58875e0ea9f41fc177f2286dddc95ab
author Eric Anholt <eric@anholt.net> 1478300318 -0700
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1490526356 +0200

drm/vc4: Use runtime autosuspend to avoid thrashing V3D power state.

commit 3a62234680d86efa0239665ed8a0e908f1aef147 upstream.

The pm_runtime_put() we were using immediately released power on the
device, which meant that we were generally turning the device off and
on once per frame.  In many profiles I've looked at, that added up to
about 1% of CPU time, but this could get worse in the case of frequent
rendering and readback (as may happen in X rendering).  By keeping the
device on until we've been idle for a couple of frames, we drop the
overhead of runtime PM down to sub-.1%.

Signed-off-by: Eric Anholt <eric@anholt.net>
Cc: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>