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 <[email protected]>
> Signed-off-by: Hans de Goede <[email protected]>Patch looks good to me, so Acked-by: Pali Rohár <[email protected]> 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, -- Pali Rohár [email protected]
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