drm/i915: load a ring frequency scaling table v3

The ring frequency scaling table tells the PCU to treat certain GPU
frequencies as if they were a given CPU frequency for purposes of
scaling the ring frequency.  Normally the PCU will scale the ring
frequency based on the CPU P-state, but with the table present, it will
also take the GPU frequency into account.

The main downside of keeping the ring frequency high while the CPU is
at a low frequency (or asleep altogether) is increased power
consumption.  But then if you're keeping your GPU busy, you probably
want the extra performance.

v2:
  - add units to debug table header (from Eric)
  - use tsc_khz as a fallback if the cpufreq driver doesn't give us a freq
    (from Chris)
v3:
  - fix comments & debug output
  - remove unneeded force wake get/put

Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Tested-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/i915_suspend.c b/drivers/gpu/drm/i915/i915_suspend.c
index e8152d23d5b..6fbd997f5a6 100644
--- a/drivers/gpu/drm/i915/i915_suspend.c
+++ b/drivers/gpu/drm/i915/i915_suspend.c
@@ -875,8 +875,10 @@ int i915_restore_state(struct drm_device *dev)
 		intel_init_emon(dev);
 	}
 
-	if (IS_GEN6(dev))
+	if (IS_GEN6(dev)) {
 		gen6_enable_rps(dev_priv);
+		gen6_update_ring_freq(dev_priv);
+	}
 
 	/* Cache mode state */
 	I915_WRITE (CACHE_MODE_0, dev_priv->saveCACHE_MODE_0 | 0xffff0000);