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authorRussell King <rmk+kernel@arm.linux.org.uk>2012-01-22 20:58:55 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2012-01-22 21:10:40 +0000
commit0af5e4c36e70cfd4ae96d3704a425c414f530f2a (patch)
treeafdc1e7313af454430166d145f7a22e3e94dc961 /drivers/mfd
parentc23bb602af24a635d0894aa7091e184385bf8a9f (diff)
MFD: ucb1x00-ts: fix resume failure
If the ucb1x00 touchscreen is resumed while the touchscreen is being touched, the main thread stops responding. This occurs because two things happen: 1. When we suspended, we were woken up, and executed the loop. Finding that the touchscreen was not pressed, we prepare to schedule for a maximum timeout, before being stopped in try_to_freeze(). 2. an irq occurs, we disable the irq, and mark it as disabled, and wake the thread. This wake occurs while the thread is still within __refrigerator() 3. The thread is unfrozen, and __refrigerator() sets the threads state back to INTERRUPTIBLE. We then drop into schedule_timeout() with an infinite timeout and the IRQ disabled. This prevents any further screen touches activating the thread. Fix this by using kthread_freezable_should_stop() which handles the freezing issues for us outside of the hotspot where the task state matters. Include a flag to ignore the touchscreen until it is released to avoid sending unintended data to the application. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'drivers/mfd')
-rw-r--r--drivers/mfd/ucb1x00-ts.c32
1 files changed, 5 insertions, 27 deletions
diff --git a/drivers/mfd/ucb1x00-ts.c b/drivers/mfd/ucb1x00-ts.c
index 38ffbd50a0d..63a3cbdfa3f 100644
--- a/drivers/mfd/ucb1x00-ts.c
+++ b/drivers/mfd/ucb1x00-ts.c
@@ -47,7 +47,6 @@ struct ucb1x00_ts {
u16 x_res;
u16 y_res;
- unsigned int restart:1;
unsigned int adcsync:1;
};
@@ -207,15 +206,17 @@ static int ucb1x00_thread(void *_ts)
{
struct ucb1x00_ts *ts = _ts;
DECLARE_WAITQUEUE(wait, current);
+ bool frozen, ignore = false;
int valid = 0;
set_freezable();
add_wait_queue(&ts->irq_wait, &wait);
- while (!kthread_should_stop()) {
+ while (!kthread_freezable_should_stop(&frozen)) {
unsigned int x, y, p;
signed long timeout;
- ts->restart = 0;
+ if (frozen)
+ ignore = true;
ucb1x00_adc_enable(ts->ucb);
@@ -258,7 +259,7 @@ static int ucb1x00_thread(void *_ts)
* space. We therefore leave it to user space
* to do any filtering they please.
*/
- if (!ts->restart) {
+ if (!ignore) {
ucb1x00_ts_evt_add(ts, p, x, y);
valid = 1;
}
@@ -267,8 +268,6 @@ static int ucb1x00_thread(void *_ts)
timeout = HZ / 100;
}
- try_to_freeze();
-
schedule_timeout(timeout);
}
@@ -340,26 +339,6 @@ static void ucb1x00_ts_close(struct input_dev *idev)
ucb1x00_disable(ts->ucb);
}
-#ifdef CONFIG_PM
-static int ucb1x00_ts_resume(struct ucb1x00_dev *dev)
-{
- struct ucb1x00_ts *ts = dev->priv;
-
- if (ts->rtask != NULL) {
- /*
- * Restart the TS thread to ensure the
- * TS interrupt mode is set up again
- * after sleep.
- */
- ts->restart = 1;
- wake_up(&ts->irq_wait);
- }
- return 0;
-}
-#else
-#define ucb1x00_ts_resume NULL
-#endif
-
/*
* Initialisation.
@@ -425,7 +404,6 @@ static void ucb1x00_ts_remove(struct ucb1x00_dev *dev)
static struct ucb1x00_driver ucb1x00_ts_driver = {
.add = ucb1x00_ts_add,
.remove = ucb1x00_ts_remove,
- .resume = ucb1x00_ts_resume,
};
static int __init ucb1x00_ts_init(void)