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Input: zforce_ts - ensure that pm_stay_awake() and pm_relax() are balanced

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There is a small chance that ts->suspending flag may change while the
interrupt handler is running. To make sure call to pm_relax() is not
skipped on accident use a temporary to hold the original value at the
beginning of interrupt. Use READ_ONCE() so that the value is actually
fetched at the right time.

Tested-by: Andreas Kemnade <andreas@kemnade.info> # Tolino Shine2HD
Link: https://lore.kernel.org/r/20240824055047.1706392-8-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Dmitry Torokhov
2024-08-23 22:50:31 -07:00
parent f388412f70
commit 9ba33f6145
1 changed files with 11 additions and 5 deletions
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drivers/input/touchscreen/zforce_ts.c
+11 -5
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@@ -454,6 +454,7 @@ static irqreturn_t zforce_irq_thread(int irq, void *dev_id)
int ret;
u8 payload_buffer[FRAME_MAXSIZE];
u8 *payload;
bool suspending;
/*
* When still suspended, return.
@@ -467,7 +468,8 @@ static irqreturn_t zforce_irq_thread(int irq, void *dev_id)
dev_dbg(&client->dev, "handling interrupt\n");
/* Don't emit wakeup events from commands run by zforce_suspend */
if (!ts->suspending && device_may_wakeup(&client->dev))
suspending = READ_ONCE(ts->suspending);
if (!suspending && device_may_wakeup(&client->dev))
pm_stay_awake(&client->dev);
/*
@@ -495,7 +497,7 @@ static irqreturn_t zforce_irq_thread(int irq, void *dev_id)
* Always report touch-events received while
* suspending, when being a wakeup source
*/
if (ts->suspending && device_may_wakeup(&client->dev))
if (suspending && device_may_wakeup(&client->dev))
pm_wakeup_event(&client->dev, 500);
zforce_touch_event(ts, &payload[RESPONSE_DATA]);
break;
@@ -548,7 +550,7 @@ static irqreturn_t zforce_irq_thread(int irq, void *dev_id)
}
} while (gpiod_get_value_cansleep(ts->gpio_int));
if (!ts->suspending && device_may_wakeup(&client->dev))
if (!suspending && device_may_wakeup(&client->dev))
pm_relax(&client->dev);
dev_dbg(&client->dev, "finished interrupt\n");
@@ -584,7 +586,9 @@ static int zforce_suspend(struct device *dev)
int ret = 0;
mutex_lock(&input->mutex);
ts->suspending = true;
WRITE_ONCE(ts->suspending, true);
smp_mb();
/*
* When configured as a wakeup source device should always wake
@@ -615,7 +619,9 @@ static int zforce_suspend(struct device *dev)
ts->suspended = true;
unlock:
ts->suspending = false;
smp_mb();
WRITE_ONCE(ts->suspending, false);
mutex_unlock(&input->mutex);
return ret;