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From: Christian Loehle <christian.loehle@arm.com>
To: linux-pm@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	rafael@kernel.org
Cc: vincent.guittot@linaro.org,
	qyousef@layalina.io,
	peterz@infradead.org,
	daniel.lezcano@linaro.org,
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	kajetan.puchalski@arm.com,
	lukasz.luba@arm.com,
	dietmar.eggemann@arm.com,
	Christian Loehle <christian.loehle@arm.com>
Subject: [PATCH 3/6] cpuidle: teo: Don't always stop tick on one state
Date: Thu,  6 Jun 2024 10:00:47 +0100
Message-Id: <20240606090050.327614-4-christian.loehle@arm.com>
In-Reply-To: <20240606090050.327614-1-christian.loehle@arm.com>
References: <20240606090050.327614-1-christian.loehle@arm.com>
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Even if we have only one state, we unfortunately still need to query
expected sleep length if state0 is a proper sleep state like WFI.
This enables teo to save energy even in that scenario.

Signed-off-by: Christian Loehle <christian.loehle@arm.com>
---
 drivers/cpuidle/governors/teo.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/cpuidle/governors/teo.c b/drivers/cpuidle/governors/teo.c
index 2c427dd4cac0..216d34747e3b 100644
--- a/drivers/cpuidle/governors/teo.c
+++ b/drivers/cpuidle/governors/teo.c
@@ -403,7 +403,14 @@ static int teo_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
 	/* Check if there is any choice in the first place. */
 	if (drv->state_count < 2) {
 		idx = 0;
-		goto out_tick;
+		if (drv->states[0].flags & CPUIDLE_FLAG_POLLING)
+			goto out_tick;
+		/*
+		 * If we only have one state and it is a proper one, check if
+		 * disabling the tick would be worth it.
+		 */
+		duration_ns = tick_nohz_get_sleep_length(&delta_tick);
+		goto end;
 	}

 	if (!dev->states_usage[0].disable)
--
2.34.1