[PATCH libinput] touchpad: add quirk for the T450 and T460 generation hardware

Peter Hutterer peter.hutterer at who-t.net
Wed Mar 16 23:52:43 UTC 2016


On Wed, Mar 16, 2016 at 10:57:53AM +0100, Hans de Goede wrote:
> Hi,
> 
> On 11-03-16 01:24, Peter Hutterer wrote:
> >The touchpad's sensors are too far apart (or the firmware interferes), causing
> >in a jerky movement visible especially on slow motion. We get a bunch of
> >normal motion events, then only ABS_MT_PRESSURE updates without x/y updates.
> >After about one mm of movement x/y updates resume, with the first event
> >covering the distance between the last motion event. That event is usually
> >accelerated and thus causes a large jump. Subsequent events are sufficiently
> >fine-grained again.
> >
> >This patch counts the number of non-motion events. Once we hit 10 in a row, we
> >mark the first motion update as non-dirty, effectively discarding the motion
> >and thus stopping the pointer jumps.
> >
> >https://bugs.freedesktop.org/show_bug.cgi?id=94379
> >
> >Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
> >Tested-by: Benjamin Tissoires <benjamin.tissoires at gmail.com>
> >---
> >  src/evdev-mt-touchpad.c            | 32 ++++++++++++++++++++++++++++----
> >  src/evdev-mt-touchpad.h            | 12 ++++++++++++
> >  src/evdev.c                        |  1 +
> >  src/evdev.h                        |  1 +
> >  udev/90-libinput-model-quirks.hwdb |  7 +++++++
> >  5 files changed, 49 insertions(+), 4 deletions(-)
> >
> >diff --git a/src/evdev-mt-touchpad.c b/src/evdev-mt-touchpad.c
> >index 00d6539..d0a8e27 100644
> >--- a/src/evdev-mt-touchpad.c
> >+++ b/src/evdev-mt-touchpad.c
> >@@ -337,7 +337,7 @@ tp_process_absolute(struct tp_dispatch *tp,
> >  	case ABS_MT_PRESSURE:
> >  		t->pressure = e->value;
> >  		t->dirty = true;
> >-		tp->queued |= TOUCHPAD_EVENT_MOTION;
> >+		tp->queued |= TOUCHPAD_EVENT_OTHERAXIS;
> >  		break;
> >  	}
> >  }
> >@@ -880,8 +880,10 @@ tp_position_fake_touches(struct tp_dispatch *tp)
> >  }
> >
> >  static inline bool
> >-tp_need_motion_history_reset(struct tp_dispatch *tp)
> >+tp_need_motion_history_reset(struct tp_dispatch *tp, uint64_t time)
> >  {
> >+	bool rc = false;
> >+
> >  	/* semi-mt finger postions may "jump" when nfingers changes */
> >  	if (tp->semi_mt && tp->nfingers_down != tp->old_nfingers_down)
> >  		return true;
> >@@ -894,7 +896,29 @@ tp_need_motion_history_reset(struct tp_dispatch *tp)
> >  		 tp->old_nfingers_down > tp->num_slots))
> >  		return true;
> >
> >-	return false;
> >+	/* Quirk: if we had multiple events without x/y axis
> >+	   information, the next x/y event is going to be a jump. So we
> >+	   reset that touch to non-dirty effectively swallowing that event
> >+	   and restarting with the next event again.
> >+	 */
> >+	if (tp->device->model_flags & EVDEV_MODEL_LENOVO_T450_TOUCHPAD) {
> >+		if (tp->queued & TOUCHPAD_EVENT_MOTION) {
> >+			if (tp->quirks.nonmotion_event_count > 10) {
> >+				struct tp_touch *t;
> >+
> >+				tp_for_each_touch(tp, t)
> >+				t->dirty = false;
> >+				rc = true;
> >+			}
> >+			tp->quirks.nonmotion_event_count = 0;
> >+		}
> >+
> >+		if ((tp->queued & (TOUCHPAD_EVENT_OTHERAXIS|TOUCHPAD_EVENT_MOTION)) ==
> 
> You could make this line:
> 
> 		else if (tp->queued & TOUCHPAD_EVENT_OTHERAXIS)
> 
> Since you reset tp->quirks.nonmotion_event_count above it makes sense
> IMHO to do the increment in an else-if.

true, I didn't see that. I've already pushed the patch though so I'll leave
it for now, will probably clean it up at some time in the future.

> Also you're not using the time parameter you're adding to this function.

oh, right. I'll push that out as follow-up. for the archives, v2 of that
patch experimented with a timeout on top of this approach but that ended up
not being necessary/useful.

thanks

Cheers,
   Peter

> 
> >+		    TOUCHPAD_EVENT_OTHERAXIS)
> >+			tp->quirks.nonmotion_event_count++;
> >+	}
> >+
> >+	return rc;
> >  }
> >
> >  static void
> >@@ -909,7 +933,7 @@ tp_process_state(struct tp_dispatch *tp, uint64_t time)
> >  	tp_unhover_touches(tp, time);
> >  	tp_position_fake_touches(tp);
> >
> >-	want_motion_reset = tp_need_motion_history_reset(tp);
> >+	want_motion_reset = tp_need_motion_history_reset(tp, time);
> >
> >  	for (i = 0; i < tp->ntouches; i++) {
> >  		t = tp_get_touch(tp, i);
> >diff --git a/src/evdev-mt-touchpad.h b/src/evdev-mt-touchpad.h
> >index eae327b..1f05a03 100644
> >--- a/src/evdev-mt-touchpad.h
> >+++ b/src/evdev-mt-touchpad.h
> >@@ -41,6 +41,7 @@ enum touchpad_event {
> >  	TOUCHPAD_EVENT_MOTION		= (1 << 0),
> >  	TOUCHPAD_EVENT_BUTTON_PRESS	= (1 << 1),
> >  	TOUCHPAD_EVENT_BUTTON_RELEASE	= (1 << 2),
> >+	TOUCHPAD_EVENT_OTHERAXIS	= (1 << 3),
> >  };
> >
> >  enum touchpad_model {
> >@@ -353,6 +354,17 @@ struct tp_dispatch {
> >  		int upper_thumb_line;
> >  		int lower_thumb_line;
> >  	} thumb;
> >+
> >+	struct {
> >+		/* A quirk used on the T450 series Synaptics hardware.
> >+		 * Slowly moving the finger causes multiple events with only
> >+		 * ABS_MT_PRESSURE but no x/y information. When the x/y
> >+		 * event comes, it will be a jump of ~20 units. We use the
> >+		 * below to count non-motion events to discard that first
> >+		 * event with the jump.
> >+		 */
> >+		unsigned int nonmotion_event_count;
> >+	} quirks;
> >  };
> >
> >  #define tp_for_each_touch(_tp, _t) \
> >diff --git a/src/evdev.c b/src/evdev.c
> >index 51768fe..a5c965d 100644
> >--- a/src/evdev.c
> >+++ b/src/evdev.c
> >@@ -1680,6 +1680,7 @@ evdev_read_model_flags(struct evdev_device *device)
> >  		{ "LIBINPUT_MODEL_CYBORG_RAT", EVDEV_MODEL_CYBORG_RAT },
> >  		{ "LIBINPUT_MODEL_CYAPA", EVDEV_MODEL_CYAPA },
> >  		{ "LIBINPUT_MODEL_ALPS_RUSHMORE", EVDEV_MODEL_ALPS_RUSHMORE },
> >+		{ "LIBINPUT_MODEL_LENOVO_T450_TOUCHPAD", EVDEV_MODEL_LENOVO_T450_TOUCHPAD },
> >  		{ NULL, EVDEV_MODEL_DEFAULT },
> >  	};
> >  	const struct model_map *m = model_map;
> >diff --git a/src/evdev.h b/src/evdev.h
> >index 482712b..4a5d807 100644
> >--- a/src/evdev.h
> >+++ b/src/evdev.h
> >@@ -113,6 +113,7 @@ enum evdev_device_model {
> >  	EVDEV_MODEL_CYBORG_RAT = (1 << 14),
> >  	EVDEV_MODEL_CYAPA = (1 << 15),
> >  	EVDEV_MODEL_ALPS_RUSHMORE = (1 << 16),
> >+	EVDEV_MODEL_LENOVO_T450_TOUCHPAD= (1 << 17),
> >  };
> >
> >  struct mt_slot {
> >diff --git a/udev/90-libinput-model-quirks.hwdb b/udev/90-libinput-model-quirks.hwdb
> >index eb2859e..d5978f7 100644
> >--- a/udev/90-libinput-model-quirks.hwdb
> >+++ b/udev/90-libinput-model-quirks.hwdb
> >@@ -100,6 +100,13 @@ libinput:name:Cypress APA Trackpad (cyapa):dmi:*
> >  libinput:name:SynPS/2 Synaptics TouchPad:dmi:*svnLENOVO:*:pvrThinkPadX230*
> >   LIBINPUT_MODEL_LENOVO_X230=1
> >
> >+# Lenovo T450/T460 and all other Lenovos of the *50 and *60 generation,
> >+# including the X1 Carbon 3rd gen
> >+libinput:name:SynPS/2 Synaptics TouchPad:dmi:*svnLENOVO:*:pvrThinkPad??50*:
> >+libinput:name:SynPS/2 Synaptics TouchPad:dmi:*svnLENOVO:*:pvrThinkPad??60*:
> >+libinput:name:SynPS/2 Synaptics TouchPad:dmi:*svnLENOVO:*:pvrThinkPadX1Carbon3rd:*
> >+ LIBINPUT_MODEL_LENOVO_T450_TOUCHPAD=1
> >+
> >  ##########################################
> >  # Synaptics
> >  ##########################################
> 
> Otherwise this patch looks good to me and is:
> 
> Reviewed-by: Hans de Goede <hdegoede at redhat.com>
> 
> Regards,
> 
> Hans


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