drm/i915/gt: Restore aggressive post-boost downclocking

We reduced the clocks slowly after a boost event based on the
observation that the smoothness of animations suffered. However, since
reducing the evalution intervals, we should be able to respond to the
rapidly fluctuating workload of a simple desktop animation and so
restore the more aggressive downclocking.

References: 2a8862d2 ("drm/i915: Reduce the RPS shock")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200429205446.3259-6-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gt/intel_rps.c

@@ -1680,30 +1680,18 @@ static void rps_work(struct work_struct *work)
 		adj = 0;
 	}
 
-	rps->last_adj = adj;
-
 	/*
-	 * Limit deboosting and boosting to keep ourselves at the extremes
-	 * when in the respective power modes (i.e. slowly decrease frequencies
-	 * while in the HIGH_POWER zone and slowly increase frequencies while
-	 * in the LOW_POWER zone). On idle, we will hit the timeout and drop
-	 * to the next level quickly, and conversely if busy we expect to
-	 * hit a waitboost and rapidly switch into max power.
-	 */
-	if ((adj < 0 && rps->power.mode == HIGH_POWER) ||
-	    (adj > 0 && rps->power.mode == LOW_POWER))
-		rps->last_adj = 0;
-
-	/* sysfs frequency interfaces may have snuck in while servicing the
-	 * interrupt
+	 * sysfs frequency limits may have snuck in while
+	 * servicing the interrupt
 	 */
 	new_freq += adj;
 	new_freq = clamp_t(int, new_freq, min, max);
 
 	if (intel_rps_set(rps, new_freq)) {
 		drm_dbg(&i915->drm, "Failed to set new GPU frequency\n");
-		rps->last_adj = 0;
+		adj = 0;
 	}
+	rps->last_adj = adj;
 
 	mutex_unlock(&rps->lock);