[Intel-gfx] [PATCH v2 2/4] drm/i915: Keep min freq above floor on HSW/BDW

[Tom.O'Rourke at intel.com]

From: Tom O'Rourke <Tom.O'Rourke at intel.com>

Set the min_freq_softlimit to max(RPe, 450MHz).

Setting a floor can ensure a minimum experience
level.  The 450MHz value came from a power and
performance study of various types of workloads
(3D, Media, GPGPU, idle, etc).

v2: rebased

Signed-off-by: Tom O'Rourke <Tom.O'Rourke at intel.com>
---
 drivers/gpu/drm/i915/intel_pm.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 2434542..9f9afb3 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4649,7 +4649,8 @@ static void gen6_init_rps_frequencies(struct drm_device *dev)
 	if (dev_priv->rps.min_freq_softlimit == 0) {
 		if (IS_HASWELL(dev) || IS_BROADWELL(dev))
 			dev_priv->rps.min_freq_softlimit =
-				dev_priv->rps.efficient_freq;
+				/* max(RPe, 450 MHz) */
+				max(dev_priv->rps.efficient_freq, (u8) 9);
 		else
 			dev_priv->rps.min_freq_softlimit =
 				dev_priv->rps.min_freq;
-- 
1.7.9.5