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author | Marek Vasut <marex@denx.de> | 2015-05-08 07:25:49 +0200 |
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committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2015-05-22 02:06:13 +0200 |
commit | 77b071e7931dd762563ac74e3e448b2aef23ad2f (patch) | |
tree | 24853e0f28a3ceb3706a41aba4686c68141aee76 /drivers/input/touchscreen/stmpe-ts.c | |
parent | Input: smtpe-ts - use msecs_to_jiffies() instead of HZ (diff) | |
download | linux-77b071e7931dd762563ac74e3e448b2aef23ad2f.tar.xz linux-77b071e7931dd762563ac74e3e448b2aef23ad2f.zip |
Input: smtpe-ts - wait 50mS until polling for pen-up
Wait a little bit longer, 50mS instead of 20mS, until the driver starts
polling for pen-up. The problematic behavior before this patch is applied
is as follows. The behavior was observed on the STMPE610QTR controller.
Upon a physical pen-down event, the touchscreen reports one set of x-y-p
coordinates and a pen-down event. After that, the pen-up polling is
triggered and since the controller is not ready yet, the polling mistakenly
detects a pen-up event while the physical state is still such that the pen
is down on the touch surface.
The pen-up handling flushes the controller FIFO, so after that, all the
samples in the controller are discarded. The controller becomes ready
shortly after this bogus pen-up handling and does generate again a pen-down
interrupt. This time, the controller contains x-y-p samples which all read
as zero. Since pressure value is zero, this set of samples is effectively
ignored by userland.
In the end, the driver just bounces between pen-down and bogus pen-up
handling, generating no useful results. Fix this by giving the controller a
bit more time before polling it for pen-up.
Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Diffstat (limited to '')
-rw-r--r-- | drivers/input/touchscreen/stmpe-ts.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/input/touchscreen/stmpe-ts.c b/drivers/input/touchscreen/stmpe-ts.c index 702ad200d916..e4c31256a74d 100644 --- a/drivers/input/touchscreen/stmpe-ts.c +++ b/drivers/input/touchscreen/stmpe-ts.c @@ -164,7 +164,7 @@ static irqreturn_t stmpe_ts_handler(int irq, void *data) STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN); /* start polling for touch_det to detect release */ - schedule_delayed_work(&ts->work, msecs_to_jiffies(20)); + schedule_delayed_work(&ts->work, msecs_to_jiffies(50)); return IRQ_HANDLED; } |