drm/i915/bdw: Set initial rps freq to RP1

Programming it outside of the rp0-rp1 range is considered a programming
error. Since we do not know that the previous value would actually be in
the range, program something we've read from the hardware, and therefore
know will work.

This is potentially an issue for platforms whose ranges are outside the
norms given in the programming guide (ie. early silicon)

v2: Use RP1 instead of RPn
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_pm.c

@@ -3279,8 +3279,10 @@ static void gen8_enable_rps(struct drm_device *dev)
 				    rc6_mask);
 
 	/* 4 Program defaults and thresholds for RPS*/
-	I915_WRITE(GEN6_RPNSWREQ, HSW_FREQUENCY(10)); /* Request 500 MHz */
-	I915_WRITE(GEN6_RC_VIDEO_FREQ, HSW_FREQUENCY(12)); /* Request 600 MHz */
+	I915_WRITE(GEN6_RPNSWREQ,
+		   HSW_FREQUENCY(dev_priv->rps.rp1_freq));
+	I915_WRITE(GEN6_RC_VIDEO_FREQ,
+		   HSW_FREQUENCY(dev_priv->rps.rp1_freq));
 	/* NB: Docs say 1s, and 1000000 - which aren't equivalent */
 	I915_WRITE(GEN6_RP_DOWN_TIMEOUT, 100000000 / 128); /* 1 second timeout */