linux-kernel - [PATCH v9 18/19] PM / devfreq: tegra30: Tune up MCCPU boost-down coefficient

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Date:   Tue,  5 Nov 2019 00:56:16 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Tomeu Vizoso <tomeu.vizoso@...labora.com>,
        Peter Geis <pgwipeout@...il.com>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>
Cc:     linux-pm@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v9 18/19] PM / devfreq: tegra30: Tune up MCCPU boost-down coefficient

MCCPU boosts up very aggressively by 800% and boosts down very mildly by
10%. This doesn't work well when system is idling because the very slow
de-boosting results in lots of consecutive-down interrupts, in result
memory stays clocked high and CPU doesn't enter deepest idling state
instead of keeping memory at lowest freq and having CPU cluster turned
off. A more faster de-boosting fixes the case of idling system and doesn't
affect the case of an active system.

Reviewed-by: Chanwoo Choi <cw00.choi@...sung.com>
Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 drivers/devfreq/tegra30-devfreq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
index e44f1a48f838..0b65f89d74d5 100644
--- a/drivers/devfreq/tegra30-devfreq.c
+++ b/drivers/devfreq/tegra30-devfreq.c
@@ -124,7 +124,7 @@ static const struct tegra_devfreq_device_config actmon_device_configs[] = {
 		.offset = 0x200,
 		.irq_mask = 1 << 25,
 		.boost_up_coeff = 800,
-		.boost_down_coeff = 90,
+		.boost_down_coeff = 40,
 		.boost_up_threshold = 27,
 		.boost_down_threshold = 10,
 		.avg_dependency_threshold = 16000, /* 16MHz in kHz units */
-- 
2.23.0