diff options
| -rw-r--r-- | drivers/gpu/drm/i915/intel_pm.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 4b12637e2084..ccdea53210c0 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -5004,8 +5004,18 @@ static void vlv_set_rps_idle(struct drm_i915_private *dev_priv) if (dev_priv->rps.cur_freq <= val) return; - /* Wake up the media well, as that takes a lot less - * power than the Render well. */ + /* The punit delays the write of the frequency and voltage until it + * determines the GPU is awake. During normal usage we don't want to + * waste power changing the frequency if the GPU is sleeping (rc6). + * However, the GPU and driver is now idle and we do not want to delay + * switching to minimum voltage (reducing power whilst idle) as we do + * not expect to be woken in the near future and so must flush the + * change by waking the device. + * + * We choose to take the media powerwell (either would do to trick the + * punit into committing the voltage change) as that takes a lot less + * power than the render powerwell. + */ intel_uncore_forcewake_get(dev_priv, FORCEWAKE_MEDIA); valleyview_set_rps(dev_priv, val); intel_uncore_forcewake_put(dev_priv, FORCEWAKE_MEDIA); |