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author | Russell King <rmk+kernel@arm.linux.org.uk> | 2012-01-22 20:58:55 (GMT) |
---|---|---|
committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2012-01-22 21:10:40 (GMT) |
commit | 0af5e4c36e70cfd4ae96d3704a425c414f530f2a (patch) | |
tree | afdc1e7313af454430166d145f7a22e3e94dc961 /drivers/mfd | |
parent | c23bb602af24a635d0894aa7091e184385bf8a9f (diff) | |
download | linux-fsl-qoriq-0af5e4c36e70cfd4ae96d3704a425c414f530f2a.tar.xz |
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.c | 32 |
1 files changed, 5 insertions, 27 deletions
diff --git a/drivers/mfd/ucb1x00-ts.c b/drivers/mfd/ucb1x00-ts.c index 38ffbd5..63a3cbd 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) |