Re: [PATCH v8] psmouse - focaltech pass finger width to userspace

[Dmitry Tunin <hanipouspilot@gmail.com>]

> 
> Hi,
> 
> Some comments below. If it is not a problem that width values are
> outdated as soon as there are two or more fingers on the touchpad, I
> think the change is good.
> 
> Regards,
> Mathias
> 
> Am 24.04.2015 um 01:15 schrieb Dmitry Tunin:
>> Focaltech touchpads report finger width in packet[5] of absolute packet.
>> Range for width in raw format is 0x10 - 0x70. Second half-byte is always 0.
>> 0xff is reported, when a large contact area is detected.
>> This can be handled in userspace.
>>
>> Signed-off-by: Dmitry Tunin <hanipouspilot@gmail.com>
>> ---
>>  drivers/input/mouse/focaltech.c | 16 ++++++++++++++--
>>  1 file changed, 14 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/input/mouse/focaltech.c b/drivers/input/mouse/focaltech.c
>> index 23d2594..ea53f8b 100644
>> --- a/drivers/input/mouse/focaltech.c
>> +++ b/drivers/input/mouse/focaltech.c
>> @@ -90,6 +90,13 @@ struct focaltech_finger_state {
>>  	 */
>>  	unsigned int x;
>>  	unsigned int y;
>> +
>> +	/*
>> +	* Finger width 0-7 and 15 for 'latching'
> You already describe below that 15 is latched - what you write above
> should probably rather be something like "15 if a very large contact
> area was detected" or something like that.

OK. No problem.
>> +	* 15 value stays until the finger is released
>> +	* Width is reported only in absolute packets
>> +	*/
>> +	unsigned int width;
>>  };
>>  
>>  /*
>> @@ -112,7 +119,7 @@ struct focaltech_data {
>>  	struct focaltech_hw_state state;
>>  };
>>  
>> -static void focaltech_report_state(struct psmouse *psmouse)
>> +static void focaltech_report_state(struct psmouse *psmouse, bool abs)
>>  {
>>  	struct focaltech_data *priv = psmouse->private;
>>  	struct focaltech_hw_state *state = &priv->state;
>> @@ -137,6 +144,7 @@ static void focaltech_report_state(struct psmouse *psmouse)
>>  			input_report_abs(dev, ABS_MT_POSITION_X, clamped_x);
>>  			input_report_abs(dev, ABS_MT_POSITION_Y,
>>  					 priv->y_max - clamped_y);
>> +			if (abs) input_report_abs(dev, ABS_TOOL_WIDTH, state->width);
> You are sending width here for *all* fingers, even though only one
> finger has an up-to-date width value. Is that intentional? I fail to see
> how that is different from always sending width no matter the packet
> type, because in any case all but one fingers will have an outdated
> width value.

That is not true. Width is reported only in abs packets. So I report width for a specific 
finger. If multiple fingers are active, this data becomes outdated, when rel packets are processed.
But we can do nothing with that. The only doubt I have, that we do not need to store all that finger width in
struct  focaltech_finger_state. It is overkill.
The only reason for that is to process a situation, when there is one 'thin' touch and another 'palm' touch.
Userspace driver may ignore the palm, but keep processing a finger. Various userspace drivers can behave in a different way.
But this is rare. I can move width *all* value to hw_state and forget of each packets. Just report the last one.
In practice it should not make much difference.

I already committed this change to ppa with dkms driver, and it can be tested by people.

>>  		}
>>  	}
>>  	input_mt_report_pointer_emulation(dev, true);
>> @@ -187,6 +195,7 @@ static void focaltech_process_abs_packet(struct psmouse *psmouse,
>>  
>>  	state->fingers[finger].x = ((packet[1] & 0xf) << 8) | packet[2];
>>  	state->fingers[finger].y = (packet[3] << 8) | packet[4];
>> +	state->fingers[finger].width = packet[5] >> 4;
>>  	state->fingers[finger].valid = true;
>>  }
>>  
>> @@ -228,14 +237,17 @@ static void focaltech_process_packet(struct psmouse *psmouse)
>>  	switch (packet[0] & 0xf) {
>>  	case FOC_TOUCH:
>>  		focaltech_process_touch_packet(psmouse, packet);
>> +		focaltech_report_state(psmouse, false);
>>  		break;
>>  
>>  	case FOC_ABS:
>>  		focaltech_process_abs_packet(psmouse, packet);
>> +		focaltech_report_state(psmouse, true);
>>  		break;
>>  
>>  	case FOC_REL:
>>  		focaltech_process_rel_packet(psmouse, packet);
>> +		focaltech_report_state(psmouse, false);
>>  		break;
>>  
>>  	default:
>> @@ -243,7 +255,6 @@ static void focaltech_process_packet(struct psmouse *psmouse)
>>  		break;
>>  	}
>>  
> Remove that blank line as well? :)
>> -	focaltech_report_state(psmouse);
>>  }
>>  
>>  static psmouse_ret_t focaltech_process_byte(struct psmouse *psmouse)
>> @@ -331,6 +342,7 @@ static void focaltech_set_input_params(struct psmouse *psmouse)
>>  	__set_bit(EV_ABS, dev->evbit);
>>  	input_set_abs_params(dev, ABS_MT_POSITION_X, 0, priv->x_max, 0, 0);
>>  	input_set_abs_params(dev, ABS_MT_POSITION_Y, 0, priv->y_max, 0, 0);
>> +	input_set_abs_params(dev, ABS_TOOL_WIDTH, 0, 15, 0, 0);
>>  	input_mt_init_slots(dev, 5, INPUT_MT_POINTER);
>>  	__set_bit(INPUT_PROP_BUTTONPAD, dev->propbit);
>>  }
> 

Various mistakes in commits are because I have too many trees and versions. 3.16, 3.19 and two dkms, which are a bit different.
I need to learn sorting that out.

After someone of maintainers finds time to look at this, I will make a final version.