[PATCH libinput] touchpad: disable 2fg scrolling on semi-mt touchpads
Benjamin Tissoires
benjamin.tissoires at gmail.com
Wed Jul 15 08:44:47 PDT 2015
On Mon, Jul 13, 2015 at 11:39 PM, Peter Hutterer
<peter.hutterer at who-t.net> wrote:
> These touchpads have a terrible resolution when two fingers are down, causing
> scrolling to jump around a lot. That then turns into bug reports that we can't
> do much about, the data is simply garbage.
>
> For Alps:
> https://bugs.freedesktop.org/show_bug.cgi?id=91081
> For Synaptics:
> https://bugs.freedesktop.org/show_bug.cgi?id=91135
>
> Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
> ---
This patch is Acked-by: Benjamin Tissoires <benjamin.tissoires at gmail.com>
FWIW, here is the list of semi-mt devices the kernel exports (and that
will have 2 fg scrolling disabled by this patch):
- Alps touchpads from firmware version 3 to 5 (6 seems to report
single touch data anyway)
- all Cypress PS/2 touchpads
- Elantech touchpads from firmware version 2 to 3
- the Sentelic touchpads that are reporting MT data
- some early Synaptics touchpads with advanced gestures that are not
image sensor
Just brace yourself for users complaining about missing functionality :)
Cheers,
Benjamin
> doc/scrolling.dox | 7 +++++++
> src/evdev-mt-touchpad.c | 35 ++++++++++++++++++++++++++++-------
> test/touchpad.c | 23 +++++++++++++----------
> 3 files changed, 48 insertions(+), 17 deletions(-)
>
> diff --git a/doc/scrolling.dox b/doc/scrolling.dox
> index 658fe4b..10f5331 100644
> --- a/doc/scrolling.dox
> +++ b/doc/scrolling.dox
> @@ -44,6 +44,13 @@ movements will translate into tiny scroll movements.
> Scrolling in both directions at once is possible by meeting the required
> distance thresholds to enable each direction separately.
>
> +Two-finger scrolling requires the touchpad to track both touch points with
> +reasonable precision. Unfortunately, so-called "semi-mt" touchpads can only
> +track the bounding box of the two fingers rather than the actual position of
> +each finger. In addition, that bounding box usually suffers from a
> +low resolution, causing jumpy movement during two-finger scrolling. libinput
> +does not provide two-finger scrolling on those touchpads.
> +
> @section edge_scrolling Edge scrolling
>
> On some touchpads, edge scrolling is available, triggered by moving a single
> diff --git a/src/evdev-mt-touchpad.c b/src/evdev-mt-touchpad.c
> index bbba665..4ab57f2 100644
> --- a/src/evdev-mt-touchpad.c
> +++ b/src/evdev-mt-touchpad.c
> @@ -1370,18 +1370,27 @@ tp_init_accel(struct tp_dispatch *tp, double diagonal)
> }
>
> static uint32_t
> -tp_scroll_config_scroll_method_get_methods(struct libinput_device *device)
> +tp_scroll_get_methods(struct tp_dispatch *tp)
> {
> - struct evdev_device *evdev = (struct evdev_device*)device;
> - struct tp_dispatch *tp = (struct tp_dispatch*)evdev->dispatch;
> uint32_t methods = LIBINPUT_CONFIG_SCROLL_EDGE;
>
> - if (tp->ntouches >= 2)
> + /* semi-mt touchpads have a terrible 2fg resolution, causing
> + * scroll jumps */
> + if (tp->ntouches >= 2 && !tp->semi_mt)
> methods |= LIBINPUT_CONFIG_SCROLL_2FG;
>
> return methods;
> }
>
> +static uint32_t
> +tp_scroll_config_scroll_method_get_methods(struct libinput_device *device)
> +{
> + struct evdev_device *evdev = (struct evdev_device*)device;
> + struct tp_dispatch *tp = (struct tp_dispatch*)evdev->dispatch;
> +
> + return tp_scroll_get_methods(tp);
> +}
> +
> static enum libinput_config_status
> tp_scroll_config_scroll_method_set_method(struct libinput_device *device,
> enum libinput_config_scroll_method method)
> @@ -1413,10 +1422,22 @@ tp_scroll_config_scroll_method_get_method(struct libinput_device *device)
> static enum libinput_config_scroll_method
> tp_scroll_get_default_method(struct tp_dispatch *tp)
> {
> - if (tp->ntouches >= 2)
> - return LIBINPUT_CONFIG_SCROLL_2FG;
> + uint32_t methods;
> + enum libinput_config_scroll_method method;
> +
> + methods = tp_scroll_get_methods(tp);
> +
> + if (tp->ntouches >= 2 &&
> + (methods & LIBINPUT_CONFIG_SCROLL_2FG))
> + method = LIBINPUT_CONFIG_SCROLL_2FG;
> else
> - return LIBINPUT_CONFIG_SCROLL_EDGE;
> + method = LIBINPUT_CONFIG_SCROLL_EDGE;
> +
> + if ((methods & method) == 0)
> + log_bug_libinput(tp_libinput_context(tp),
> + "Invalid default scroll method %d\n",
> + method);
> + return method;
> }
>
> static enum libinput_config_scroll_method
> diff --git a/test/touchpad.c b/test/touchpad.c
> index 7058bea..78eb022 100644
> --- a/test/touchpad.c
> +++ b/test/touchpad.c
> @@ -1530,7 +1530,7 @@ START_TEST(touchpad_scroll_natural_enable_config)
> }
> END_TEST
>
> -START_TEST(touchpad_scroll_natural)
> +START_TEST(touchpad_scroll_natural_2fg)
> {
> struct litest_device *dev = litest_current_device();
> struct libinput *li = dev->libinput;
> @@ -1603,10 +1603,12 @@ START_TEST(touchpad_scroll_defaults)
>
> method = libinput_device_config_scroll_get_methods(device);
> ck_assert(method & LIBINPUT_CONFIG_SCROLL_EDGE);
> - if (libevdev_get_num_slots(evdev) > 1)
> + if (libevdev_get_num_slots(evdev) > 1 &&
> + !libevdev_has_property(evdev, INPUT_PROP_SEMI_MT))
> ck_assert(method & LIBINPUT_CONFIG_SCROLL_2FG);
>
> - if (libevdev_get_num_slots(evdev) > 1)
> + if (libevdev_get_num_slots(evdev) > 1 &&
> + !libevdev_has_property(evdev, INPUT_PROP_SEMI_MT))
> expected = LIBINPUT_CONFIG_SCROLL_2FG;
> else
> expected = LIBINPUT_CONFIG_SCROLL_EDGE;
> @@ -1622,7 +1624,8 @@ START_TEST(touchpad_scroll_defaults)
> status = libinput_device_config_scroll_set_method(device,
> LIBINPUT_CONFIG_SCROLL_2FG);
>
> - if (libevdev_get_num_slots(evdev) > 1)
> + if (libevdev_get_num_slots(evdev) > 1 &&
> + !libevdev_has_property(evdev, INPUT_PROP_SEMI_MT))
> ck_assert_int_eq(status, LIBINPUT_CONFIG_STATUS_SUCCESS);
> else
> ck_assert_int_eq(status, LIBINPUT_CONFIG_STATUS_UNSUPPORTED);
> @@ -4187,14 +4190,14 @@ litest_setup_tests(void)
> litest_add("touchpad:topsoftbuttons", clickpad_topsoftbuttons_clickfinger, LITEST_TOPBUTTONPAD, LITEST_ANY);
> litest_add("touchpad:topsoftbuttons", clickpad_topsoftbuttons_clickfinger_dev_disabled, LITEST_TOPBUTTONPAD, LITEST_ANY);
>
> - litest_add("touchpad:scroll", touchpad_2fg_scroll, LITEST_TOUCHPAD, LITEST_SINGLE_TOUCH);
> - litest_add("touchpad:scroll", touchpad_2fg_scroll_slow_distance, LITEST_TOUCHPAD, LITEST_SINGLE_TOUCH);
> - litest_add("touchpad:scroll", touchpad_2fg_scroll_return_to_motion, LITEST_TOUCHPAD, LITEST_SINGLE_TOUCH);
> - litest_add("touchpad:scroll", touchpad_2fg_scroll_source, LITEST_TOUCHPAD, LITEST_SINGLE_TOUCH);
> - litest_add("touchpad:scroll", touchpad_2fg_scroll_semi_mt, LITEST_SEMI_MT, LITEST_SINGLE_TOUCH);
> + litest_add("touchpad:scroll", touchpad_2fg_scroll, LITEST_TOUCHPAD, LITEST_SINGLE_TOUCH|LITEST_SEMI_MT);
> + litest_add("touchpad:scroll", touchpad_2fg_scroll_slow_distance, LITEST_TOUCHPAD, LITEST_SINGLE_TOUCH|LITEST_SEMI_MT);
> + litest_add("touchpad:scroll", touchpad_2fg_scroll_return_to_motion, LITEST_TOUCHPAD, LITEST_SINGLE_TOUCH|LITEST_SEMI_MT);
> + litest_add("touchpad:scroll", touchpad_2fg_scroll_source, LITEST_TOUCHPAD, LITEST_SINGLE_TOUCH|LITEST_SEMI_MT);
> + litest_add("touchpad:scroll", touchpad_2fg_scroll_semi_mt, LITEST_SEMI_MT, LITEST_SINGLE_TOUCH|LITEST_SEMI_MT);
> litest_add("touchpad:scroll", touchpad_scroll_natural_defaults, LITEST_TOUCHPAD, LITEST_ANY);
> litest_add("touchpad:scroll", touchpad_scroll_natural_enable_config, LITEST_TOUCHPAD, LITEST_ANY);
> - litest_add("touchpad:scroll", touchpad_scroll_natural, LITEST_TOUCHPAD, LITEST_SINGLE_TOUCH);
> + litest_add("touchpad:scroll", touchpad_scroll_natural_2fg, LITEST_TOUCHPAD, LITEST_SINGLE_TOUCH|LITEST_SEMI_MT);
> litest_add("touchpad:scroll", touchpad_scroll_defaults, LITEST_TOUCHPAD, LITEST_ANY);
> litest_add("touchpad:scroll", touchpad_edge_scroll, LITEST_TOUCHPAD, LITEST_ANY);
> litest_add("touchpad:scroll", touchpad_edge_scroll_no_motion, LITEST_TOUCHPAD, LITEST_ANY);
> --
> 2.4.3
>
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