| Message ID | 1457002322-21953-1-git-send-email-m.grzeschik@pengutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Mar 03, 2016 at 11:52:02AM +0100, Michael Grzeschik wrote: > It is possible that da9052_ts_input_open is called and the touchscreen > is triggering continuous interrupts. In this case we will never leave > da9052_ts_input_open. The da9052_reg_update will never get the i2c bus > as the interrupt handler will continuously lock it. > > This patch switch places of da9052_reg_update and the setting of > tsi->stopped. This way its ensured that da9052_ts_input_open will never > lockup on interrupt flood. I understand what you are saying about updating register, however I do not understand why we would want to swap unmasking pendown event ans clearing the "stopped" flag. Thanks. > > Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de> > --- > drivers/input/touchscreen/da9052_tsi.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/drivers/input/touchscreen/da9052_tsi.c b/drivers/input/touchscreen/da9052_tsi.c > index 5a013bb..1b136b8 100644 > --- a/drivers/input/touchscreen/da9052_tsi.c > +++ b/drivers/input/touchscreen/da9052_tsi.c > @@ -189,17 +189,20 @@ static int da9052_configure_tsi(struct da9052_tsi *tsi) > > static int da9052_ts_input_open(struct input_dev *input_dev) > { > + int val; > struct da9052_tsi *tsi = input_get_drvdata(input_dev); > > - tsi->stopped = false; > - mb(); > + val = da9052_reg_update(tsi->da9052, DA9052_TSI_CONT_A_REG, > + 1 << 1, 1 << 1); > > /* Unmask PEN_DOWN event */ > da9052_enable_irq(tsi->da9052, DA9052_IRQ_PENDOWN); > > + tsi->stopped = false; > + mb(); > + > /* Enable Pen Detect Circuit */ > - return da9052_reg_update(tsi->da9052, DA9052_TSI_CONT_A_REG, > - 1 << 1, 1 << 1); > + return val; > } > > static void da9052_ts_input_close(struct input_dev *input_dev) > -- > 2.7.0 >
On Fri, Mar 11, 2016 at 11:33:11AM -0800, Dmitry Torokhov wrote: > On Thu, Mar 03, 2016 at 11:52:02AM +0100, Michael Grzeschik wrote: > > It is possible that da9052_ts_input_open is called and the touchscreen > > is triggering continuous interrupts. In this case we will never leave > > da9052_ts_input_open. The da9052_reg_update will never get the i2c bus > > as the interrupt handler will continuously lock it. > > > > This patch switch places of da9052_reg_update and the setting of > > tsi->stopped. This way its ensured that da9052_ts_input_open will never > > lockup on interrupt flood. > > I understand what you are saying about updating register, however I do > not understand why we would want to swap unmasking pendown event ans > clearing the "stopped" flag. The "stopped" flag has an locking purpose in the irq handler. My patch ensures that the irq handler will not trigger any da9052_reg_update before da9052_ts_input_open has finished. On second thought, it would probably be enough to swap the call of da9052_reg_update and da9052_enable_irq in da9052_ts_input_open. This will have the same effect. I will send an corrected v2. Thanks, Michael
diff --git a/drivers/input/touchscreen/da9052_tsi.c b/drivers/input/touchscreen/da9052_tsi.c index 5a013bb..1b136b8 100644 --- a/drivers/input/touchscreen/da9052_tsi.c +++ b/drivers/input/touchscreen/da9052_tsi.c @@ -189,17 +189,20 @@ static int da9052_configure_tsi(struct da9052_tsi *tsi) static int da9052_ts_input_open(struct input_dev *input_dev) { + int val; struct da9052_tsi *tsi = input_get_drvdata(input_dev); - tsi->stopped = false; - mb(); + val = da9052_reg_update(tsi->da9052, DA9052_TSI_CONT_A_REG, + 1 << 1, 1 << 1); /* Unmask PEN_DOWN event */ da9052_enable_irq(tsi->da9052, DA9052_IRQ_PENDOWN); + tsi->stopped = false; + mb(); + /* Enable Pen Detect Circuit */ - return da9052_reg_update(tsi->da9052, DA9052_TSI_CONT_A_REG, - 1 << 1, 1 << 1); + return val; } static void da9052_ts_input_close(struct input_dev *input_dev)
It is possible that da9052_ts_input_open is called and the touchscreen is triggering continuous interrupts. In this case we will never leave da9052_ts_input_open. The da9052_reg_update will never get the i2c bus as the interrupt handler will continuously lock it. This patch switch places of da9052_reg_update and the setting of tsi->stopped. This way its ensured that da9052_ts_input_open will never lockup on interrupt flood. Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de> --- drivers/input/touchscreen/da9052_tsi.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)