[PATCH libinput 3/3] Extract and reset the abs fuzz value for the x/y axes
Peter Hutterer
peter.hutterer at who-t.net
Mon Mar 5 04:38:02 UTC 2018
The kernel fuzz handling is buggy, especially when we want to rely on the fuzz
value for our hysteresis. But since this is a hw property and (at least
sometimes) set by the driver, we can't make this a pure libinput hwdb set
either.
So our workaround is:
* extract the (non-zero) fuzz into a udev property so we don't lose it
* set the fuzz to 0 to disable the in-kernel hysteresis
* overwrite our internal absinfo with the property fuzz
This way we get to use the hw-specified fuzz without having the kernel muck
around with it. We also get to use the EVDEV_ABS_ values in 60-evdev.hwdb to
override a driver-set fuzz.
Two drawbacks:
- we're resetting the kernel fuzz to 0, this affects any other users of the
device node. That's probably a minor impact only.
- we can only save this in a udev property there's a risk of this information
getting lost when playing around with udev rules. That too should be a minor
issue.
https://bugs.freedesktop.org/show_bug.cgi?id=105303
Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
meson.build | 2 +-
src/evdev.c | 39 +++++++++++++++++++++++
src/evdev.h | 3 ++
udev/90-libinput-model-quirks.rules.in | 1 -
udev/libinput-model-quirks.c | 58 ++++++++++++++++++++++++++++++++++
5 files changed, 101 insertions(+), 2 deletions(-)
diff --git a/meson.build b/meson.build
index 60caf997..1c12fe1c 100644
--- a/meson.build
+++ b/meson.build
@@ -87,7 +87,7 @@ executable('libinput-device-group',
install_dir : udev_dir)
executable('libinput-model-quirks',
'udev/libinput-model-quirks.c',
- dependencies : dep_udev,
+ dependencies : [dep_udev, dep_libevdev],
include_directories : [includes_src, includes_include],
install : true,
install_dir : udev_dir)
diff --git a/src/evdev.c b/src/evdev.c
index 257824aa..40a5d975 100644
--- a/src/evdev.c
+++ b/src/evdev.c
@@ -1505,6 +1505,7 @@ static void
evdev_extract_abs_axes(struct evdev_device *device)
{
struct libevdev *evdev = device->evdev;
+ int fuzz;
if (!libevdev_has_event_code(evdev, EV_ABS, ABS_X) ||
!libevdev_has_event_code(evdev, EV_ABS, ABS_Y))
@@ -1512,6 +1513,12 @@ evdev_extract_abs_axes(struct evdev_device *device)
if (evdev_fix_abs_resolution(device, ABS_X, ABS_Y))
device->abs.is_fake_resolution = true;
+
+ if ((fuzz = evdev_read_fuzz_prop(device, ABS_X)))
+ libevdev_set_abs_fuzz(evdev, ABS_X, fuzz);
+ if ((fuzz = evdev_read_fuzz_prop(device, ABS_Y)))
+ libevdev_set_abs_fuzz(evdev, ABS_Y, fuzz);
+
device->abs.absinfo_x = libevdev_get_abs_info(evdev, ABS_X);
device->abs.absinfo_y = libevdev_get_abs_info(evdev, ABS_Y);
device->abs.dimensions.x = abs(device->abs.absinfo_x->maximum -
@@ -1529,6 +1536,11 @@ evdev_extract_abs_axes(struct evdev_device *device)
ABS_MT_POSITION_Y))
device->abs.is_fake_resolution = true;
+ if ((fuzz = evdev_read_fuzz_prop(device, ABS_MT_POSITION_X)))
+ libevdev_set_abs_fuzz(evdev, ABS_X, fuzz);
+ if ((fuzz = evdev_read_fuzz_prop(device, ABS_MT_POSITION_Y)))
+ libevdev_set_abs_fuzz(evdev, ABS_Y, fuzz);
+
device->abs.absinfo_x = libevdev_get_abs_info(evdev, ABS_MT_POSITION_X);
device->abs.absinfo_y = libevdev_get_abs_info(evdev, ABS_MT_POSITION_Y);
device->abs.dimensions.x = abs(device->abs.absinfo_x->maximum -
@@ -2162,6 +2174,33 @@ evdev_read_calibration_prop(struct evdev_device *device)
calibration[5]);
}
+int
+evdev_read_fuzz_prop(struct evdev_device *device, unsigned int code)
+{
+ const char *prop;
+ char name[32];
+ int rc;
+ int fuzz = 0;
+
+ rc = snprintf(name, sizeof(name), "LIBINPUT_FUZZ_%02x", code);
+ if (rc == -1)
+ return 0;
+
+ prop = udev_device_get_property_value(device->udev_device, name);
+ if (prop == NULL)
+ return 0;
+
+ rc = safe_atoi(prop, &fuzz);
+ if (rc == -1 || fuzz < 0) {
+ evdev_log_bug_libinput(device,
+ "invalid LIBINPUT_FUZZ property value: %s\n",
+ prop);
+ return 0;
+ }
+
+ return fuzz;
+}
+
bool
evdev_device_has_capability(struct evdev_device *device,
enum libinput_device_capability capability)
diff --git a/src/evdev.h b/src/evdev.h
index 7fc21690..e5361ad2 100644
--- a/src/evdev.h
+++ b/src/evdev.h
@@ -378,6 +378,9 @@ evdev_init_calibration(struct evdev_device *device,
void
evdev_read_calibration_prop(struct evdev_device *device);
+int
+evdev_read_fuzz_prop(struct evdev_device *device, unsigned int code);
+
enum switch_reliability
evdev_read_switch_reliability_prop(struct evdev_device *device);
diff --git a/udev/90-libinput-model-quirks.rules.in b/udev/90-libinput-model-quirks.rules.in
index e7d56bbe..5ddc0ba4 100644
--- a/udev/90-libinput-model-quirks.rules.in
+++ b/udev/90-libinput-model-quirks.rules.in
@@ -15,7 +15,6 @@ KERNEL!="event*", GOTO="libinput_model_quirks_end"
# First, run the program and import the LIBINPUT_MODEL_FIRMWARE_VERSION
# environment (if any)
KERNELS=="*input*", \
- ENV{ID_INPUT_TOUCHPAD}=="1", \
IMPORT{program}="@UDEV_TEST_PATH at libinput-model-quirks %S%p"
# Second, match on anything with that env set and import from the hwdb
diff --git a/udev/libinput-model-quirks.c b/udev/libinput-model-quirks.c
index 2dc917d5..d1d5a68a 100644
--- a/udev/libinput-model-quirks.c
+++ b/udev/libinput-model-quirks.c
@@ -31,6 +31,7 @@
#include <unistd.h>
#include <libudev.h>
#include <linux/input.h>
+#include <libevdev/libevdev.h>
#include "libinput-util.h"
@@ -107,6 +108,61 @@ handle_touchpad(struct udev_device *device)
handle_touchpad_synaptics(device);
}
+/**
+ * For a non-zero fuzz on the x/y axes, print that fuzz as property and
+ * reset the kernel's fuzz to 0.
+ * https://bugs.freedesktop.org/show_bug.cgi?id=105202
+ */
+static void
+handle_absfuzz(struct udev_device *device)
+{
+ const char *devnode;
+ struct libevdev *evdev = NULL;
+ int fd = -1;
+ int rc;
+ unsigned int *code;
+ unsigned int axes[] = {ABS_X,
+ ABS_Y,
+ ABS_MT_POSITION_X,
+ ABS_MT_POSITION_Y};
+
+ devnode = udev_device_get_devnode(device);
+ if (!devnode)
+ goto out;
+
+ fd = open(devnode, O_RDWR);
+ if (fd == -1 && errno == EACCES)
+ fd = open(devnode, O_RDONLY);
+ if (fd < 0)
+ goto out;
+
+ rc = libevdev_new_from_fd(fd, &evdev);
+ if (rc != 0)
+ goto out;
+
+ if (!libevdev_has_event_type(evdev, EV_ABS))
+ goto out;
+
+ ARRAY_FOR_EACH(axes, code) {
+ struct input_absinfo abs;
+ int fuzz;
+
+ fuzz = libevdev_get_abs_fuzz(evdev, *code);
+ if (!fuzz)
+ continue;
+
+ abs = *libevdev_get_abs_info(evdev, *code);
+ abs.fuzz = 0;
+ libevdev_kernel_set_abs_info(evdev, *code, &abs);
+
+ printf("LIBINPUT_FUZZ_%02x=%d\n", *code, fuzz);
+ }
+
+out:
+ close(fd);
+ libevdev_free(evdev);
+}
+
int main(int argc, char **argv)
{
int rc = 1;
@@ -127,6 +183,8 @@ int main(int argc, char **argv)
if (!device)
goto out;
+ handle_absfuzz(device);
+
if (prop_value(device, "ID_INPUT_TOUCHPAD"))
handle_touchpad(device);
--
2.14.3
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