Hi Peter,
On Mon, Apr 10, 2017 at 11:52:26AM +0200, Peter Fink wrote:
> STMPE driver with STMPE811 reported x=0/y=0 when clicking in succession at
> higher speeds. In some configurations the consuming X11 input stack is able
> to ignore this input, but e.g. with inverted axes this is prone to fail.
>
> In these cases it might happen that even applications are closed when the
> close-X is located in the same corner as touch 0/0 is mapped to. This
> happens when touch coordinates are read from an empty fifo although the
> threshold interrupt indicates that new data is available.
>
> To avoid wrong touch data read and evaluate the fifo_empty bit before
> accessing the fifo.
>
> Signed-off-by: Peter Fink <pfink@xxxxxxxxxxxx>
> ---
> drivers/input/touchscreen/stmpe-ts.c | 24 +++++++++++++++---------
> 1 file changed, 15 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/input/touchscreen/stmpe-ts.c b/drivers/input/touchscreen/stmpe-ts.c
> index 2a78e27..dcc9d48 100644
> --- a/drivers/input/touchscreen/stmpe-ts.c
> +++ b/drivers/input/touchscreen/stmpe-ts.c
> @@ -44,6 +44,7 @@
> #define OP_MOD_XYZ 0
>
> #define STMPE_TSC_CTRL_TSC_EN (1<<0)
> +#define STMPE_FIFO_EMPTY (1<<5)
This belongs with other FIFO STA register definitions, please move
there. Also, all these could be converted to BIT().
>
> #define STMPE_FIFO_STA_RESET (1<<0)
>
> @@ -175,17 +176,22 @@ static irqreturn_t stmpe_ts_handler(int irq, void *data)
> stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
> STMPE_TSC_CTRL_TSC_EN, 0);
>
> - stmpe_block_read(ts->stmpe, STMPE_REG_TSC_DATA_XYZ, 4, data_set);
> + if (!(stmpe_reg_read(ts->stmpe, STMPE_REG_FIFO_STA)
> + & STMPE_FIFO_EMPTY)) {
We probably want to check for errors. So:
fifo_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_FIFO_STA);
if (fifo_sta >= 0 && !(fifo_sta & STMPE_FIFO_EMPTY)) {
...
}
I am also looking at stmpe_work() and wonder if we should not check FIFO
status when we see touch detect and if we see it there we probably want
to bail?
Thanks.
--
Dmitry
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