Re: [PATCH v1] Input: touchscreen: ads7846.c: Fix race that causes missing releases
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: 2020-10-27 03:48:56
Also in:
lkml
Hi Oleksij, On Mon, Oct 26, 2020 at 02:21:17PM +0100, Oleksij Rempel wrote:
quoted hunk ↗ jump to hunk
From: David Jander <redacted> If touchscreen is released while busy reading HWMON device, the release can be missed. The IRQ thread is not started because no touch is active and BTN_TOUCH release event is never sent. Fixes: f5a28a7d4858f94a ("Input: ads7846 - avoid pen up/down when reading hwmon") Co-Developed-by: David Jander <redacted> Signed-off-by: David Jander <redacted> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> --- drivers/input/touchscreen/ads7846.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c index ea31956f3a90..0236a119c52d 100644 --- a/drivers/input/touchscreen/ads7846.c +++ b/drivers/input/touchscreen/ads7846.c@@ -211,10 +211,26 @@ static void ads7846_stop(struct ads7846 *ts) } } +static int get_pendown_state(struct ads7846 *ts);
Not a fan forward declarations, just move the definition if needed.
+
/* Must be called with ts->lock held */
static void ads7846_restart(struct ads7846 *ts)
{
+ unsigned int pdstate;I do not see it being used. Do you have more patches for the driver?
+
if (!ts->disabled && !ts->suspended) {
+ /* Check if pen was released since last stop */
+ if (ts->pendown && !get_pendown_state(ts)) {
+ struct input_dev *input = ts->input;
+
+ input_report_key(input, BTN_TOUCH, 0);
+ input_report_abs(input, ABS_PRESSURE, 0);
+ input_sync(input);
+
+ ts->pendown = false;
+ dev_vdbg(&ts->spi->dev, "UP\n");I wonder if we should not have ads7846_report_pen_up(struct ads7846 *ts)
+ } + /* Tell IRQ thread that it may poll the device. */ ts->stopped = false; mb(); -- 2.28.0
Thanks. -- Dmitry