From 0af5e4c36e70cfd4ae96d3704a425c414f530f2a Mon Sep 17 00:00:00 2001 From: Russell King Date: Sun, 22 Jan 2012 20:58:55 +0000 Subject: 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 --- drivers/mfd/ucb1x00-ts.c | 32 +++++--------------------------- 1 file changed, 5 insertions(+), 27 deletions(-) (limited to 'drivers/mfd') diff --git a/drivers/mfd/ucb1x00-ts.c b/drivers/mfd/ucb1x00-ts.c index 38ffbd50a0d2..63a3cbdfa3f3 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) -- cgit v1.2.3