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Groups > linux.kernel > #1723134

[PATCH 05/13] thermal/drivers/hisi: Fix multiple alarm interrupts firing

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The DT specifies a threshold of 65000, we setup the register with a value in
the temperature resolution for the controller, 64656.

When we reach 64656, the interrupt fires, the interrupt is disabled. Then the
irq thread runs and calls thermal_zone_device_update() which will call in turn
hisi_thermal_get_temp().

The function will look if the temperature decreased, assuming it was more than
65000, but that is not the case because the current temperature is 64656
(because of the rounding when setting the threshold). This condition being
true, we re-enable the interrupt which fires immediately after exiting the irq
thread. That happens again and again until the temperature goes to more than
65000.

Potentially, there is here an interrupt storm if the temperature stabilizes at
this temperature. A very unlikely case but possible.

In any case, it does not make sense to handle dozens of alarm interrupt for
nothing.

Fix this by rounding the threshold value to the controller resolution so the
check against the threshold is consistent with the one set in the controller.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/thermal/hisi_thermal.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/thermal/hisi_thermal.c b/drivers/thermal/hisi_thermal.c
index b58ad40..524310d 100644
--- a/drivers/thermal/hisi_thermal.c
+++ b/drivers/thermal/hisi_thermal.c
@@ -90,6 +90,12 @@ static inline long hisi_thermal_temp_to_step(long temp)
 	return (temp - HISI_TEMP_BASE) / HISI_TEMP_STEP;
 }
 
+static inline long hisi_thermal_round_temp(int temp)
+{
+	return hisi_thermal_step_to_temp(
+		hisi_thermal_temp_to_step(temp));
+}
+
 static long hisi_thermal_get_sensor_temp(struct hisi_thermal_data *data,
 					 struct hisi_thermal_sensor *sensor)
 {
@@ -221,7 +227,7 @@ static irqreturn_t hisi_thermal_alarm_irq_thread(int irq, void *dev)
 	sensor = &data->sensors;
 
 	dev_crit(&data->pdev->dev, "THERMAL ALARM: T > %d\n",
-		 sensor->thres_temp / 1000);
+		 sensor->thres_temp);
 	mutex_unlock(&data->thermal_lock);
 
 	thermal_zone_device_update(data->sensors.tzd,
@@ -255,7 +261,7 @@ static int hisi_thermal_register_sensor(struct platform_device *pdev,
 
 	for (i = 0; i < of_thermal_get_ntrips(sensor->tzd); i++) {
 		if (trip[i].type == THERMAL_TRIP_PASSIVE) {
-			sensor->thres_temp = trip[i].temperature;
+			sensor->thres_temp = hisi_thermal_round_temp(trip[i].temperature);
 			break;
 		}
 	}
-- 
2.7.4

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Thread

[PATCH 01/13] thermal/drivers/hisi: Fix missing interrupt enablement Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-08-30 10:50 +0200
  [PATCH 02/13] thermal/drivers/hisi: Remove the multiple sensors support Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-08-30 10:50 +0200
    Re: [PATCH 02/13] thermal/drivers/hisi: Remove the multiple sensors  support Leo Yan <leo.yan@linaro.org> - 2017-09-01 16:10 +0200
      Re: [PATCH 02/13] thermal/drivers/hisi: Remove the multiple sensors  support Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-09-01 22:50 +0200
  [PATCH 06/13] thermal/drivers/hisi: Remove pointless lock Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-08-30 11:00 +0200
    Re: [PATCH 06/13] thermal/drivers/hisi: Remove pointless lock Leo Yan <leo.yan@linaro.org> - 2017-09-01 16:50 +0200
  [PATCH 03/13] thermal/drivers/hisi: Fix kernel panic on alarm interrupt Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-08-30 11:00 +0200
    Re: [PATCH 03/13] thermal/drivers/hisi: Fix kernel panic on alarm  interrupt Leo Yan <leo.yan@linaro.org> - 2017-09-01 16:20 +0200
  [PATCH 08/13] thermal/drivers/hisi: Fix configuration register setting Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-08-30 11:00 +0200
    Re: [PATCH 08/13] thermal/drivers/hisi: Fix configuration register  setting Leo Yan <leo.yan@linaro.org> - 2017-09-02 05:00 +0200
      Re: [PATCH 08/13] thermal/drivers/hisi: Fix configuration register  setting Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-09-02 10:40 +0200
        Re: [PATCH 08/13] thermal/drivers/hisi: Fix configuration register  setting Leo Yan <leo.yan@linaro.org> - 2017-09-04 03:00 +0200
          Re: [PATCH 08/13] thermal/drivers/hisi: Fix configuration register  setting Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-09-04 11:20 +0200
  [PATCH 09/13] thermal/drivers/hisi: Remove costly sensor inspection Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-08-30 11:00 +0200
    Re: [PATCH 09/13] thermal/drivers/hisi: Remove costly sensor  inspection Leo Yan <leo.yan@linaro.org> - 2017-09-02 05:30 +0200
      Re: [PATCH 09/13] thermal/drivers/hisi: Remove costly sensor  inspection Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-09-02 15:20 +0200
        Re: [PATCH 09/13] thermal/drivers/hisi: Remove costly sensor  inspection Leo Yan <leo.yan@linaro.org> - 2017-09-04 03:00 +0200
          Re: [PATCH 09/13] thermal/drivers/hisi: Remove costly sensor  inspection Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-09-04 13:30 +0200
            Re: [PATCH 09/13] thermal/drivers/hisi: Remove costly sensor  inspection Leo Yan <leo.yan@linaro.org> - 2017-09-04 16:40 +0200
  [PATCH 05/13] thermal/drivers/hisi: Fix multiple alarm interrupts firing Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-08-30 11:00 +0200
    Re: [PATCH 05/13] thermal/drivers/hisi: Fix multiple alarm  interrupts firing Leo Yan <leo.yan@linaro.org> - 2017-09-01 16:50 +0200
  Re: [PATCH 01/13] thermal/drivers/hisi: Fix missing interrupt  enablement Leo Yan <leo.yan@linaro.org> - 2017-09-01 10:40 +0200

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