lkml.org 
[lkml]   [2020]   [Nov]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2] Input: touchscreen: ads7846.c: Fix race that causes missing releases
Hello Dmitry,

ping for this patch. Are there some changes needed?

Regards,
Oleksij

On Tue, Oct 27, 2020 at 11:54:16AM +0100, Oleksij Rempel wrote:
> From: David Jander <david@protonic.nl>
>
> 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 <david@protonic.nl>
> Signed-off-by: David Jander <david@protonic.nl>
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> ---
> drivers/input/touchscreen/ads7846.c | 44 +++++++++++++++++------------
> 1 file changed, 26 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
> index f2dc2c8ab5ec..4164a9834b59 100644
> --- a/drivers/input/touchscreen/ads7846.c
> +++ b/drivers/input/touchscreen/ads7846.c
> @@ -199,6 +199,26 @@ struct ads7846 {
> #define REF_ON (READ_12BIT_DFR(x, 1, 1))
> #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
>
> +static int get_pendown_state(struct ads7846 *ts)
> +{
> + if (ts->get_pendown_state)
> + return ts->get_pendown_state();
> +
> + return !gpio_get_value(ts->gpio_pendown);
> +}
> +
> +static void ads7846_report_pen_up(struct ads7846 *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");
> +}
> +
> /* Must be called with ts->lock held */
> static void ads7846_stop(struct ads7846 *ts)
> {
> @@ -215,6 +235,10 @@ static void ads7846_stop(struct ads7846 *ts)
> static void ads7846_restart(struct ads7846 *ts)
> {
> if (!ts->disabled && !ts->suspended) {
> + /* Check if pen was released since last stop */
> + if (ts->pendown && !get_pendown_state(ts))
> + ads7846_report_pen_up(ts);
> +
> /* Tell IRQ thread that it may poll the device. */
> ts->stopped = false;
> mb();
> @@ -606,14 +630,6 @@ static const struct attribute_group ads784x_attr_group = {
>
> /*--------------------------------------------------------------------------*/
>
> -static int get_pendown_state(struct ads7846 *ts)
> -{
> - if (ts->get_pendown_state)
> - return ts->get_pendown_state();
> -
> - return !gpio_get_value(ts->gpio_pendown);
> -}
> -
> static void null_wait_for_sync(void)
> {
> }
> @@ -868,16 +884,8 @@ static irqreturn_t ads7846_irq(int irq, void *handle)
> msecs_to_jiffies(TS_POLL_PERIOD));
> }
>
> - if (ts->pendown && !ts->stopped) {
> - 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");
> - }
> + if (ts->pendown && !ts->stopped)
> + ads7846_report_pen_up(ts);
>
> return IRQ_HANDLED;
> }
> --
> 2.28.0
>
>

--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |

\
 
 \ /
  Last update: 2020-11-09 12:01    [W:1.141 / U:1.104 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site