From 02e08c407a33a4b4b45a6a899b8da31c63c442b6 Mon Sep 17 00:00:00 2001

From: Peter Hutterer <peter.hutterer@who-t.net>

Date: Thu, 19 Mar 2015 14:19:58 +1000

Subject: [PATCH] udev: builtin-keyboard: add support for EVDEV_ABS_*

Parse properties in the form

EVDEV_ABS_00="<min>:<max>:<res>:<fuzz>:<flat>"

and apply them to the kernel device. Future processes that open that device

will see the updated EV_ABS range.

This is particularly useful for touchpads that don't provide a resolution in

the kernel driver but can be fixed up through hwdb entries (e.g. bcm5974).

All values in the property are optional, e.g. a string of "::45" is valid to

set the resolution to 45.

The order intentionally orders resolution before fuzz and flat despite it

being the last element in the absinfo struct. The use-case for setting

fuzz/flat is almost non-existent, resolution is probably the most common case

we'll need.

To avoid multiple hwdb invocations for the same device, replace the

hwdb "keyboard:" prefix with "evdev:" and drop the separate 60-keyboard.rules

file. The new 60-evdev.rules is called for all event nodes

anyway, we don't need a separate rules file and second callout to the hwdb

builtin.

(cherry picked from commit 51c0c2869845a058268d54c3111d55d0dd485704)

Changes to 51c0c28698:

- leave 60-keyboard.rules in place. This forces a double callout to the

  keyboard builtin but avoids breaking current setups that rely on the

  keyboard: prefix

- drop the AT keyboard matching rule from 60-evdev.rules, this is for keyboard

  matches and handled by the 60-keyboard.rules that was restored with the

  backport.

---

 Makefile.am                      |  2 +

 hwdb/60-evdev.hwdb               | 37 +++++++++++++++++

 rules/60-evdev.rules             | 14 +++++++

 src/udev/udev-builtin-keyboard.c | 86 ++++++++++++++++++++++++++++++++++++++--

 4 files changed, 135 insertions(+), 4 deletions(-)

 create mode 100644 hwdb/60-evdev.hwdb

 create mode 100644 rules/60-evdev.rules

diff --git a/Makefile.am b/Makefile.am

index c18c79e115..77e2e4d7ab 100644

--- a/Makefile.am

+++ b/Makefile.am

@@ -3555,6 +3555,7 @@ dist_udevrules_DATA += \

 	rules/42-usb-hid-pm.rules \

 	rules/50-udev-default.rules \

 	rules/60-drm.rules \

+	rules/60-evdev.rules \

 	rules/60-keyboard.rules \

 	rules/60-persistent-storage-tape.rules \

 	rules/60-persistent-serial.rules \

@@ -3754,6 +3755,7 @@ dist_udevhwdb_DATA = \

 	hwdb/20-acpi-vendor.hwdb \

 	hwdb/20-OUI.hwdb \

 	hwdb/20-net-ifname.hwdb \

+	hwdb/60-evdev.hwdb \

 	hwdb/60-keyboard.hwdb \

 	hwdb/70-mouse.hwdb \

 	hwdb/70-touchpad.hwdb

diff --git a/hwdb/60-evdev.hwdb b/hwdb/60-evdev.hwdb

new file mode 100644

index 0000000000..ad2d09e721

--- /dev/null

+++ b/hwdb/60-evdev.hwdb

@@ -0,0 +1,37 @@

+# This file is part of systemd.

+#

+# The lookup keys are composed in:

+#   60-evdev.rules

+#

+# Note: The format of the "evdev:" prefix match key is a

+# contract between the rules file and the hardware data, it might

+# change in later revisions to support more or better matches, it

+# is not necessarily expected to be a stable ABI.

+#

+# Match string formats:

+# evdev:<modalias>

+# evdev:name:<device name>:dmi:<dmi string>

+#

+# To add local entries, create a new file

+#   /etc/udev/hwdb.d/61-evdev-local.hwdb

+# and add your rules there. To load the new rules execute (as root):

+#   udevadm hwdb --update

+#   udevadm trigger /dev/input/eventXX

+# where /dev/input/eventXX is the device in question. If in

+# doubt, simply use /dev/input/event* to reload all input rules.

+#

+# If your changes are generally applicable, open a bug report on

+#   http://bugs.freedesktop.org/enter_bug.cgi?product=systemd

+# and include your new rules, a description of the device, and the

+# output of

+#   udevadm info /dev/input/eventXX

+# (or /dev/input/event*).

+#

+# Allowed properties are:

+#    EVDEV_ABS_<axis>=<min>:<max>:<res>:<fuzz>:<flat>

+#

+# where <axis> is the hexadecimal EV_ABS code as listed in linux/input.h

+# and min, max, res, fuzz, flat are the decimal values to the respective

+# fields of the struct input_absinfo as listed in linux/input.h.

+# If a field is missing the field will be left as-is. Not all fields need to

+# be present. e.g. ::45 sets the resolution to 45 units/mm.

diff --git a/rules/60-evdev.rules b/rules/60-evdev.rules

new file mode 100644

index 0000000000..67308ad230

--- /dev/null

+++ b/rules/60-evdev.rules

@@ -0,0 +1,14 @@

+# do not edit this file, it will be overwritten on update

+

+ACTION=="remove", GOTO="evdev_end"

+KERNEL!="event*", GOTO="evdev_end"

+

+# skip later rules when we find something for this input device

+IMPORT{builtin}="hwdb --subsystem=input --lookup-prefix=evdev:", \

+  RUN{builtin}+="keyboard", GOTO="evdev_end"

+

+# device matching the input device name and the machine's DMI data

+KERNELS=="input*", IMPORT{builtin}="hwdb 'evdev:name:$attr{name}:$attr{[dmi/id]modalias}'", \

+  RUN{builtin}+="keyboard", GOTO="evdev_end"

+

+LABEL="evdev_end"

diff --git a/src/udev/udev-builtin-keyboard.c b/src/udev/udev-builtin-keyboard.c

index 86f4018ef5..eaa21abf60 100644

--- a/src/udev/udev-builtin-keyboard.c

+++ b/src/udev/udev-builtin-keyboard.c

@@ -99,6 +99,69 @@ static void map_keycode(int fd, const char *devnode, int scancode, const char *k

                 log_error_errno(errno, "Error calling EVIOCSKEYCODE on device node '%s' (scan code 0x%x, key code %d): %m", devnode, map.scan, map.key);

 }

+static inline char* parse_token(const char *current, int32_t *val_out) {

+        char *next;

+        int32_t val;

+

+        if (!current)

+                return NULL;

+

+        val = strtol(current, &next, 0);

+        if (*next && *next != ':')

+                return NULL;

+

+        if (next != current)

+                *val_out = val;

+

+        if (*next)

+                next++;

+

+        return next;

+}

+

+static void override_abs(int fd, const char *devnode,

+                         unsigned evcode, const char *value) {

+        struct input_absinfo absinfo;

+        int rc;

+        char *next;

+

+        rc = ioctl(fd, EVIOCGABS(evcode), &absinfo);

+        if (rc < 0) {

+                log_error_errno(errno, "Error, unable to EVIOCGABS device '%s'",

+                                devnode);

+                return;

+        }

+

+        next = parse_token(value, &absinfo.minimum);

+        next = parse_token(next, &absinfo.maximum);

+        next = parse_token(next, &absinfo.resolution);

+        next = parse_token(next, &absinfo.fuzz);

+        next = parse_token(next, &absinfo.flat);

+        if (!next) {

+                log_error("Error, unable to parse EV_ABS override '%s' for '%s'\n",

+                          value, devnode);

+                return;

+        }

+

+        log_debug("keyboard: override %x with %d/%d/%d/%d/%d", evcode,

+                  absinfo.minimum, absinfo.maximum, absinfo.resolution,

+                  absinfo.fuzz, absinfo.flat);

+        rc = ioctl(fd, EVIOCSABS(evcode), &absinfo);

+        if (rc < 0)

+                log_error_errno(errno, "Error, unable to update device '%s'",

+                                devnode);

+}

+

+static int open_device(const char *devnode) {

+        int fd;

+

+        fd = open(devnode, O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);

+        if (fd < 0)

+                log_error_errno(errno, "Error, opening device '%s': %m", devnode);

+

+        return fd < 0 ? -errno : fd;

+}

+

 static int builtin_keyboard(struct udev_device *dev, int argc, char *argv[], bool test) {

         struct udev_list_entry *entry;

         unsigned release[1024];

@@ -143,14 +206,29 @@ static int builtin_keyboard(struct udev_device *dev, int argc, char *argv[], boo

                         }

                         if (fd == -1) {

-                                fd = open(node, O_RDWR|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);

-                                if (fd < 0) {

-                                        log_error_errno(errno, "Error, opening device '%s': %m", node);

+                                fd = open_device(node);

+                                if (fd < 0)

                                         return EXIT_FAILURE;

-                                }

                         }

                         map_keycode(fd, node, scancode, keycode);

+                } else if (startswith(key, "EVDEV_ABS_")) {

+                        unsigned evcode;

+

+                        /* EVDEV_ABS_<EV_ABS code>=<min>:<max>:<res>:<fuzz>:<flat> */

+                        evcode = strtoul(key + 10, &endptr, 16);

+                        if (endptr[0] != '\0') {

+                                log_error("Error, unable to parse EV_ABS code from '%s'", key);

+                                continue;

+                        }

+

+                        if (fd == -1) {

+                                fd = open_device(node);

+                                if (fd < 0)

+                                        return EXIT_FAILURE;

+                        }

+

+                        override_abs(fd, node, evcode, udev_list_entry_get_value(entry));

                 }

         }