Re: [PATCH v3] Input: elantech - fix x_max/y_max values

[Bernd Edlinger <bernd.edlinger@hotmail.de>]

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On 5/30/21 6:35 AM, Bernd Edlinger wrote:
> Since commit 37548659bb22 ("Input: elantech - query the min/max information beforehand too")
> moved the querying of the x_max/y_max values from
> elantech_set_input_params to elantech_query_info,
> the returned x_max/y_max values are different than before,
> at least for some firmware versions.
> 
> The reason is likely that this is now done before
> elantech_set_absolute_mode does run.  So it may happen that
> the returned values are exactly half of what they used to be,
> which makes input_report_abs in PS/2 mode report ABS_X values which
> exceed the x_max value, which is very annoying since the mouse stops
> to move then, and ABS_Y value become negative, which is benign.
> 
> This was observed with a MSI GX70 laptop:
> 
> elantech: assuming hardware version 3 (with firmware version 0x250f01)
> elantech: Synaptics capabilities query result 0x18, 0x17, 0x0b.
> elantech: Elan sample query result 05, 0e, 00
> input: ETPS/2 Elantech Touchpad as /devices/platform/i8042/serio...
> 
> This patch moves the code sending the ETP_FW_ID_QUERY command to
> the function elantech_set_range and calls this function in
> elantech_query_info for hw_version == 4, but for hw_version < 4 it is
> called in elantech_setup_ps2 after the function elantech_set_absolute_mode.
> 
> It is right to switch the touchpad into absolute mode first to get valid
> results from the ID query call in hardware version 2 and 3.
> 
> There is no way how this change can affect the state of the firmware
> when elantech_setup_smbus is called later, since that can only happen for
> hardware version 4, see elantech_init_smbusand elantech_use_host_notify
> which uses ETP_NEW_IC_SMBUS_HOST_NOTIFY and info->bus.
> 
> The macro ETP_NEW_IC_SMBUS_HOST_NOTIFY can only return true
> for (fw_version & 0x0f0000) == 0x0f0000 which implies v4 hardware.
> The value info->bus can only be unequal to ETP_BUS_PS2_ONLY,
> if elantech_get_resolution_v4 was called from elantech_query_info,
> which is again guarded by info->hw_version == 4.
> 
> Fixes: 37548659bb22 ("Input: elantech - query the min/max information beforehand too")
> 
> Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
> ---
> v3: Do the ID_QUEERY after set absoulute mode for hw_version < 4.
>     Note: It turned out to be more difficult to call elantech_set_absolute_mode
>     from elantech_query_info.
> 
>  drivers/input/mouse/elantech.c | 172 ++++++++++++++++++++++-------------------
>  1 file changed, 94 insertions(+), 78 deletions(-)
> 
> diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
> index 97381e2..5f4a1a4 100644
> --- a/drivers/input/mouse/elantech.c
> +++ b/drivers/input/mouse/elantech.c
> @@ -1078,6 +1078,94 @@ static int elantech_set_absolute_mode(struct psmouse *psmouse)
>  	return rc;
>  }
>  
> +static int elantech_set_range(struct psmouse *psmouse,
> +			      struct elantech_device_info *info)
> +{
> +	unsigned char param[3];
> +	unsigned char traces;
> +
> +	/* query range information */
> +	switch (info->hw_version) {
> +	case 1:
> +		info->x_min = ETP_XMIN_V1;
> +		info->y_min = ETP_YMIN_V1;
> +		info->x_max = ETP_XMAX_V1;
> +		info->y_max = ETP_YMAX_V1;
> +		break;
> +
> +	case 2:
> +		if (info->fw_version == 0x020800 ||
> +		    info->fw_version == 0x020b00 ||
> +		    info->fw_version == 0x020030) {
> +			info->x_min = ETP_XMIN_V2;
> +			info->y_min = ETP_YMIN_V2;
> +			info->x_max = ETP_XMAX_V2;
> +			info->y_max = ETP_YMAX_V2;
> +		} else {
> +			int i;
> +			int fixed_dpi;
> +
> +			i = (info->fw_version > 0x020800 &&
> +			     info->fw_version < 0x020900) ? 1 : 2;
> +
> +			if (info->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
> +				return -EINVAL;
> +
> +			fixed_dpi = param[1] & 0x10;
> +
> +			if (((info->fw_version >> 16) == 0x14) && fixed_dpi) {
> +				if (info->send_cmd(psmouse, ETP_SAMPLE_QUERY, param))
> +					return -EINVAL;
> +
> +				info->x_max = (info->capabilities[1] - i) * param[1] / 2;
> +				info->y_max = (info->capabilities[2] - i) * param[2] / 2;
> +			} else if (info->fw_version == 0x040216) {
> +				info->x_max = 819;
> +				info->y_max = 405;
> +			} else if (info->fw_version == 0x040219 || info->fw_version == 0x040215) {
> +				info->x_max = 900;
> +				info->y_max = 500;
> +			} else {
> +				info->x_max = (info->capabilities[1] - i) * 64;
> +				info->y_max = (info->capabilities[2] - i) * 64;
> +			}
> +		}
> +		break;
> +
> +	case 3:
> +		if (info->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
> +			return -EINVAL;
> +
> +		info->x_max = (0x0f & param[0]) << 8 | param[1];
> +		info->y_max = (0xf0 & param[0]) << 4 | param[2];
> +		break;
> +
> +	case 4:
> +		if (info->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
> +			return -EINVAL;
> +
> +		info->x_max = (0x0f & param[0]) << 8 | param[1];
> +		info->y_max = (0xf0 & param[0]) << 4 | param[2];
> +		traces = info->capabilities[1];
> +		if ((traces < 2) || (traces > info->x_max))
> +			return -EINVAL;
> +
> +		info->width = info->x_max / (traces - 1);
> +
> +		/* column number of traces */
> +		info->x_traces = traces;
> +
> +		/* row number of traces */
> +		traces = info->capabilities[2];
> +		if ((traces >= 2) && (traces <= info->y_max))
> +			info->y_traces = traces;
> +
> +		break;
> +	}
> +
> +	return 0;
> +}
> +
>  /*
>   * (value from firmware) * 10 + 790 = dpi
>   * we also have to convert dpi to dots/mm (*10/254 to avoid floating point)
> @@ -1659,7 +1747,6 @@ static int elantech_query_info(struct psmouse *psmouse,
>  			       struct elantech_device_info *info)
>  {
>  	unsigned char param[3];
> -	unsigned char traces;
>  	unsigned char ic_body[3];
>  
>  	memset(info, 0, sizeof(*info));
> @@ -1759,85 +1846,9 @@ static int elantech_query_info(struct psmouse *psmouse,
>  			psmouse_warn(psmouse,
>  				     "failed to query resolution data.\n");
>  		}
> -	}
> -
> -	/* query range information */
> -	switch (info->hw_version) {
> -	case 1:
> -		info->x_min = ETP_XMIN_V1;
> -		info->y_min = ETP_YMIN_V1;
> -		info->x_max = ETP_XMAX_V1;
> -		info->y_max = ETP_YMAX_V1;
> -		break;
> -
> -	case 2:
> -		if (info->fw_version == 0x020800 ||
> -		    info->fw_version == 0x020b00 ||
> -		    info->fw_version == 0x020030) {
> -			info->x_min = ETP_XMIN_V2;
> -			info->y_min = ETP_YMIN_V2;
> -			info->x_max = ETP_XMAX_V2;
> -			info->y_max = ETP_YMAX_V2;
> -		} else {
> -			int i;
> -			int fixed_dpi;
> -
> -			i = (info->fw_version > 0x020800 &&
> -			     info->fw_version < 0x020900) ? 1 : 2;
> -
> -			if (info->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
> -				return -EINVAL;
>  
> -			fixed_dpi = param[1] & 0x10;
> -
> -			if (((info->fw_version >> 16) == 0x14) && fixed_dpi) {
> -				if (info->send_cmd(psmouse, ETP_SAMPLE_QUERY, param))
> -					return -EINVAL;
> -
> -				info->x_max = (info->capabilities[1] - i) * param[1] / 2;
> -				info->y_max = (info->capabilities[2] - i) * param[2] / 2;
> -			} else if (info->fw_version == 0x040216) {
> -				info->x_max = 819;
> -				info->y_max = 405;
> -			} else if (info->fw_version == 0x040219 || info->fw_version == 0x040215) {
> -				info->x_max = 900;
> -				info->y_max = 500;
> -			} else {
> -				info->x_max = (info->capabilities[1] - i) * 64;
> -				info->y_max = (info->capabilities[2] - i) * 64;
> -			}
> -		}
> -		break;
> -
> -	case 3:
> -		if (info->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
> -			return -EINVAL;
> -
> -		info->x_max = (0x0f & param[0]) << 8 | param[1];
> -		info->y_max = (0xf0 & param[0]) << 4 | param[2];
> -		break;
> -
> -	case 4:
> -		if (info->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
> +		if (elantech_set_range(psmouse, info))
>  			return -EINVAL;
> -
> -		info->x_max = (0x0f & param[0]) << 8 | param[1];
> -		info->y_max = (0xf0 & param[0]) << 4 | param[2];
> -		traces = info->capabilities[1];
> -		if ((traces < 2) || (traces > info->x_max))
> -			return -EINVAL;
> -
> -		info->width = info->x_max / (traces - 1);
> -
> -		/* column number of traces */
> -		info->x_traces = traces;
> -
> -		/* row number of traces */
> -		traces = info->capabilities[2];
> -		if ((traces >= 2) && (traces <= info->y_max))
> -			info->y_traces = traces;
> -
> -		break;
>  	}
>  
>  	/* check for the middle button: DMI matching or new v4 firmwares */
> @@ -2037,6 +2048,11 @@ static int elantech_setup_ps2(struct psmouse *psmouse,
>  		goto init_fail;
>  	}
>  
> +	if (info->hw_version < 4) {
> +		if (elantech_set_range(psmouse, &etd->info))
> +			goto init_fail;
> +	}
> +
>  	if (info->fw_version == 0x381f17) {
>  		etd->original_set_rate = psmouse->set_rate;
>  		psmouse->set_rate = elantech_set_rate_restore_reg_07;
>