linux-kernel - Re: [PATCH 2/4] Input - synaptics: do not release extra buttons once they are pressed

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Date:	Mon, 2 Feb 2015 13:46:40 -0800
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Benjamin Tissoires <benjamin.tissoires@...hat.com>
Cc:	Hans de Goede <hdegoede@...hat.com>,
	Peter Hutterer <peter.hutterer@...-t.net>,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/4] Input - synaptics: do not release extra buttons once
 they are pressed

On Wed, Jan 28, 2015 at 03:10:05PM -0500, Benjamin Tissoires wrote:
> The current code releases the extra buttons right after they are pressed.
> As soon as a new serio report comes in, the hw state is reset to 0
> and so the buttons are released.
> 
> Check for the report type before acting on the current extra buttons
> state.

No:

"If Ext is 0 (if bit 1 of bytes 1 and 4 are the same) then there are no
external buttons being pressed (or all external buttons have been
released)." - Synaptics PS/2 TouchPad Interfacing Guide PN:
511-000275-01 Rev. B

Thanks.

> 
> Cc: stable@...r.kernel.org
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...hat.com>
> ---
>  drivers/input/mouse/synaptics.c | 10 +++++++---
>  drivers/input/mouse/synaptics.h |  3 +++
>  2 files changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
> index 0d12664..d58863b 100644
> --- a/drivers/input/mouse/synaptics.c
> +++ b/drivers/input/mouse/synaptics.c
> @@ -688,7 +688,7 @@ static int synaptics_parse_hw_state(const unsigned char buf[],
>  		}
>  
>  		if (SYN_CAP_MULTI_BUTTON_NO(priv->ext_cap) &&
> -		    ((buf[0] ^ buf[3]) & 0x02)) {
> +		    SYN_REPORT_EXT_BUTTONS(buf)) {
>  			switch (SYN_CAP_MULTI_BUTTON_NO(priv->ext_cap)) {
>  			default:
>  				/*
> @@ -792,8 +792,12 @@ static void synaptics_report_buttons(struct psmouse *psmouse,
>  		input_report_key(dev, BTN_BACK, hw->down);
>  	}
>  
> -	for (i = 0; i < SYN_CAP_MULTI_BUTTON_NO(priv->ext_cap); i++)
> -		input_report_key(dev, BTN_0 + i, hw->ext_buttons & (1 << i));
> +	if (SYN_CAP_MULTI_BUTTON_NO(priv->ext_cap) &&
> +	    SYN_REPORT_EXT_BUTTONS(psmouse->packet)) {
> +		for (i = 0; i < SYN_CAP_MULTI_BUTTON_NO(priv->ext_cap); i++)
> +			input_report_key(dev, BTN_0 + i,
> +					 hw->ext_buttons & (1 << i));
> +	}
>  }
>  
>  static void synaptics_report_mt_data(struct psmouse *psmouse,
> diff --git a/drivers/input/mouse/synaptics.h b/drivers/input/mouse/synaptics.h
> index 6faf9bb..0b2b711 100644
> --- a/drivers/input/mouse/synaptics.h
> +++ b/drivers/input/mouse/synaptics.h
> @@ -115,6 +115,9 @@
>  #define SYN_NEWABS_RELAXED		2
>  #define SYN_OLDABS			3
>  
> +/* synaptics extended button packet */
> +#define SYN_REPORT_EXT_BUTTONS(buf)	(((buf)[0] ^ (buf)[3]) & 0x02)
> +
>  /* amount to fuzz position data when touchpad reports reduced filtering */
>  #define SYN_REDUCED_FILTER_FUZZ		8
>  
> -- 
> 2.1.0
> 

-- 
Dmitry
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