Re: [PATCH] Input: synaptics-rmi4 - switch to reduced reporting mode

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Mon, Jan 20, 2020 at 12:16:28PM +0100, Lucas Stach wrote:
> When the distance thresholds are set the controller must be in reduced
> reporting mode for them to have any effect on the interrupt generation.
> This has a potentially large impact on the number of events the host
> needs to process.
> 
> Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
> ---
> I'm not sure if we want a separate DT property to allow the use of
> reduced reporting mode, as this change might lead to problems for
> controllers with unreasonably large threshold values. I'm not sure if
> any controller with bogus threshold values exist in the wild.
> ---

Andrew, any feedback on this patch?

Thanks!

>  drivers/input/rmi4/rmi_f11.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/drivers/input/rmi4/rmi_f11.c b/drivers/input/rmi4/rmi_f11.c
> index bbf9ae9f3f0c..6adea8a3e8fb 100644
> --- a/drivers/input/rmi4/rmi_f11.c
> +++ b/drivers/input/rmi4/rmi_f11.c
> @@ -412,6 +412,10 @@ struct f11_2d_sensor_queries {
>  
>  /* Defs for Ctrl0. */
>  #define RMI_F11_REPORT_MODE_MASK        0x07
> +#define RMI_F11_REPORT_MODE_CONTINUOUS  (0 << 0)
> +#define RMI_F11_REPORT_MODE_REDUCED     (1 << 0)
> +#define RMI_F11_REPORT_MODE_FS_CHANGE   (2 << 0)
> +#define RMI_F11_REPORT_MODE_FP_CHANGE   (3 << 0)
>  #define RMI_F11_ABS_POS_FILT            (1 << 3)
>  #define RMI_F11_REL_POS_FILT            (1 << 4)
>  #define RMI_F11_REL_BALLISTICS          (1 << 5)
> @@ -1195,6 +1199,16 @@ static int rmi_f11_initialize(struct rmi_function *fn)
>  		ctrl->ctrl0_11[RMI_F11_DELTA_Y_THRESHOLD] =
>  			sensor->axis_align.delta_y_threshold;
>  
> +	/*
> +	 * If distance threshold values are set, switch to reduced reporting
> +	 * mode so they actually get used by the controller.
> +	 */
> +	if (ctrl->ctrl0_11[RMI_F11_DELTA_X_THRESHOLD] ||
> +	    ctrl->ctrl0_11[RMI_F11_DELTA_Y_THRESHOLD]) {
> +		ctrl->ctrl0_11[0] &= ~RMI_F11_REPORT_MODE_MASK;
> +		ctrl->ctrl0_11[0] |= RMI_F11_REPORT_MODE_REDUCED;
> +	}
> +
>  	if (f11->sens_query.has_dribble) {
>  		switch (sensor->dribble) {
>  		case RMI_REG_STATE_OFF:
> -- 
> 2.20.1
> 

-- 
Dmitry