diff mbox

[4.0,REGRESSION,FIX] alps: Fix left touchpad button getting stuck when using it with trackpoint

Message ID 1428507532-25533-2-git-send-email-hdegoede@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Hans de Goede April 8, 2015, 3:38 p.m. UTC
When the left touchpad button gets pressed, and then the trackpoint is moved,
and then the button is released, the following happens:

1) touchpad packet is received, touchpad evdev node reports BTN_LEFT 1
2) pointingstick packet is received, the hw will report a BTN_LEFT 1 in this
   packet because when the trackstick is active it communicates the combined
   touchpad + pointingstick buttons in the trackstick packet, since
   alps_report_bare_ps2_packet passes NULL (*) for the dev2 parameter to
   alps_report_buttons the combining is not detected and the pointingstick
   evdev node will also report BTN_LEFT 1
3) on release of the button a pointingstick packet with BTN_LEFT 0 is received,
   and the pointingstick evdev node will report BTN_LEFT 0

Note how because of the passing as NULL for dev2 the touchpad evdev node
will never send BTN_LEFT 0 in this scenario leading to a stuck mouse button.

This is a regression in 4.0 introduced by commit 04aae283ba6a8
("Input: ALPS - do not mix trackstick and external PS/2 mouse data")

This commit fixes this by passing in the touchpad evdev as dev2 parameter
when calling alps_report_buttons for the pointingstick on alps v2 devices,
so that alps_report_buttons correctly detect that we're already reporting the
button as pressed via the touchpad evdev node, and will also send the release
event there.

Reported-by: Hans de Bruin <jmdebruin@xmsnet.nl>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/input/mouse/alps.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Comments

Pali Rohár April 8, 2015, 8:26 p.m. UTC | #1
On Wednesday 08 April 2015 17:38:52 Hans de Goede wrote:
> When the left touchpad button gets pressed, and then the
> trackpoint is moved, and then the button is released, the
> following happens:
> 
> 1) touchpad packet is received, touchpad evdev node reports
> BTN_LEFT 1 2) pointingstick packet is received, the hw will
> report a BTN_LEFT 1 in this packet because when the
> trackstick is active it communicates the combined touchpad +
> pointingstick buttons in the trackstick packet, since
> alps_report_bare_ps2_packet passes NULL (*) for the dev2
> parameter to alps_report_buttons the combining is not
> detected and the pointingstick evdev node will also report
> BTN_LEFT 1
> 3) on release of the button a pointingstick packet with
> BTN_LEFT 0 is received, and the pointingstick evdev node will
> report BTN_LEFT 0
> 
> Note how because of the passing as NULL for dev2 the touchpad
> evdev node will never send BTN_LEFT 0 in this scenario
> leading to a stuck mouse button.
> 
> This is a regression in 4.0 introduced by commit 04aae283ba6a8
> ("Input: ALPS - do not mix trackstick and external PS/2 mouse
> data")
> 
> This commit fixes this by passing in the touchpad evdev as
> dev2 parameter when calling alps_report_buttons for the
> pointingstick on alps v2 devices, so that alps_report_buttons
> correctly detect that we're already reporting the button as
> pressed via the touchpad evdev node, and will also send the
> release event there.
> 
> Reported-by: Hans de Bruin <jmdebruin@xmsnet.nl>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Patch looks good to me, so

Acked-by: Pali Rohár <pali.rohar@gmail.com>

As this is regression in 4.0 (which was not in 3.19), I'm also 
for fixing it. But decision is of course on maintainers...

I think this is nice example how touchpad+trackstick protocol at 
HW level should not looks like. It is complete mess what HW 
engineers invented and how their devices pass input data to 
operating system.

> ---
>  drivers/input/mouse/alps.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/input/mouse/alps.c
> b/drivers/input/mouse/alps.c index 80b6eca..6962c26 100644
> --- a/drivers/input/mouse/alps.c
> +++ b/drivers/input/mouse/alps.c
> @@ -1159,13 +1159,14 @@ static void
> alps_report_bare_ps2_packet(struct psmouse *psmouse, bool
> report_buttons)
>  {
>  	struct alps_data *priv = psmouse->private;
> -	struct input_dev *dev;
> +	struct input_dev *dev, *dev2 = NULL;
> 
>  	/* Figure out which device to use to report the bare packet
> */ if (priv->proto_version == ALPS_PROTO_V2 &&
>  	    (priv->flags & ALPS_DUALPOINT)) {
>  		/* On V2 devices the DualPoint Stick reports bare packets
> */ dev = priv->dev2;
> +		dev2 = psmouse->dev;
>  	} else if (unlikely(IS_ERR_OR_NULL(priv->dev3))) {
>  		/* Register dev3 mouse if we received PS/2 packet first
> time */ if (!IS_ERR(priv->dev3))
> @@ -1177,7 +1178,7 @@ static void
> alps_report_bare_ps2_packet(struct psmouse *psmouse, }
> 
>  	if (report_buttons)
> -		alps_report_buttons(dev, NULL,
> +		alps_report_buttons(dev, dev2,
>  				packet[0] & 1, packet[0] & 2, packet[0] & 4);
> 
>  	input_report_rel(dev, REL_X,
Dmitry Torokhov April 12, 2015, 11 p.m. UTC | #2
On Wed, Apr 08, 2015 at 10:26:36PM +0200, Pali Rohár wrote:
> On Wednesday 08 April 2015 17:38:52 Hans de Goede wrote:
> > When the left touchpad button gets pressed, and then the
> > trackpoint is moved, and then the button is released, the
> > following happens:
> > 
> > 1) touchpad packet is received, touchpad evdev node reports
> > BTN_LEFT 1 2) pointingstick packet is received, the hw will
> > report a BTN_LEFT 1 in this packet because when the
> > trackstick is active it communicates the combined touchpad +
> > pointingstick buttons in the trackstick packet, since
> > alps_report_bare_ps2_packet passes NULL (*) for the dev2
> > parameter to alps_report_buttons the combining is not
> > detected and the pointingstick evdev node will also report
> > BTN_LEFT 1
> > 3) on release of the button a pointingstick packet with
> > BTN_LEFT 0 is received, and the pointingstick evdev node will
> > report BTN_LEFT 0
> > 
> > Note how because of the passing as NULL for dev2 the touchpad
> > evdev node will never send BTN_LEFT 0 in this scenario
> > leading to a stuck mouse button.
> > 
> > This is a regression in 4.0 introduced by commit 04aae283ba6a8
> > ("Input: ALPS - do not mix trackstick and external PS/2 mouse
> > data")
> > 
> > This commit fixes this by passing in the touchpad evdev as
> > dev2 parameter when calling alps_report_buttons for the
> > pointingstick on alps v2 devices, so that alps_report_buttons
> > correctly detect that we're already reporting the button as
> > pressed via the touchpad evdev node, and will also send the
> > release event there.
> > 
> > Reported-by: Hans de Bruin <jmdebruin@xmsnet.nl>
> > Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> 
> Patch looks good to me, so
> 
> Acked-by: Pali Rohár <pali.rohar@gmail.com>
> 
> As this is regression in 4.0 (which was not in 3.19), I'm also 
> for fixing it. But decision is of course on maintainers...

Doh! Missed the 4.0 so had to tag it for stable.
diff mbox

Patch

diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c
index 80b6eca..6962c26 100644
--- a/drivers/input/mouse/alps.c
+++ b/drivers/input/mouse/alps.c
@@ -1159,13 +1159,14 @@  static void alps_report_bare_ps2_packet(struct psmouse *psmouse,
 					bool report_buttons)
 {
 	struct alps_data *priv = psmouse->private;
-	struct input_dev *dev;
+	struct input_dev *dev, *dev2 = NULL;
 
 	/* Figure out which device to use to report the bare packet */
 	if (priv->proto_version == ALPS_PROTO_V2 &&
 	    (priv->flags & ALPS_DUALPOINT)) {
 		/* On V2 devices the DualPoint Stick reports bare packets */
 		dev = priv->dev2;
+		dev2 = psmouse->dev;
 	} else if (unlikely(IS_ERR_OR_NULL(priv->dev3))) {
 		/* Register dev3 mouse if we received PS/2 packet first time */
 		if (!IS_ERR(priv->dev3))
@@ -1177,7 +1178,7 @@  static void alps_report_bare_ps2_packet(struct psmouse *psmouse,
 	}
 
 	if (report_buttons)
-		alps_report_buttons(dev, NULL,
+		alps_report_buttons(dev, dev2,
 				packet[0] & 1, packet[0] & 2, packet[0] & 4);
 
 	input_report_rel(dev, REL_X,