Re: [PATCH] da9052: ensure da9052_ts_input_open will not lock up on irq flood

[Michael Grzeschik <mgr@pengutronix.de>]

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

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