diff options
| author | Benjamin Tissoires <benjamin.tissoires@redhat.com> | 2018-10-04 15:34:30 +0300 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.cz> | 2018-10-04 22:06:45 +0300 |
| commit | d9ca1c990a7ffee7e68ab8d64efacd6c73103203 (patch) | |
| tree | a1fb65cdaff9c3e89c80adaf9aa43c36df014ad5 /include | |
| parent | 5fe2ccbef9d7aecf5c4402c753444f1a12096cfd (diff) | |
| download | linux-d9ca1c990a7ffee7e68ab8d64efacd6c73103203.tar.xz | |
Input: reserve 2 events code because of HID
Prior to commit 190d7f02ce8e ("HID: input: do not increment usages when
a duplicate is found") from the v4.18 kernel, HID used to shift the
event codes if a duplicate usage was found. This ended up in a situation
where a device would export a ton of ABS_MISC+n event codes, or a ton
of REL_MISC+n event codes.
This is now fixed, however userspace needs to detect those situation.
Fortunately, ABS_MT_SLOT-1 (ABS_MISC+6) was never assigned a code, and
so libinput can detect fake multitouch devices from genuine ones by
checking if ABS_MT_SLOT-1 is set.
Now that we have REL_WHEEL_HI_RES, libinput won't be able to differentiate
true high res mice from some other device in a pre-v4.18 kernel.
Set in stone that the ABS_MISC+6 and REL_MISC+1 are reserved and should not
be used so userspace can properly work around those old kernels.
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'include')
| -rw-r--r-- | include/uapi/linux/input-event-codes.h | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/include/uapi/linux/input-event-codes.h b/include/uapi/linux/input-event-codes.h index dad8d3890a3a..6d180cc60a5d 100644 --- a/include/uapi/linux/input-event-codes.h +++ b/include/uapi/linux/input-event-codes.h @@ -708,7 +708,15 @@ #define REL_DIAL 0x07 #define REL_WHEEL 0x08 #define REL_MISC 0x09 -#define REL_WHEEL_HI_RES 0x0a +/* + * 0x0a is reserved and should not be used in input drivers. + * It was used by HID as REL_MISC+1 and userspace needs to detect if + * the next REL_* event is correct or is just REL_MISC + n. + * We define here REL_RESERVED so userspace can rely on it and detect + * the situation described above. + */ +#define REL_RESERVED 0x0a +#define REL_WHEEL_HI_RES 0x0b #define REL_MAX 0x0f #define REL_CNT (REL_MAX+1) @@ -745,6 +753,15 @@ #define ABS_MISC 0x28 +/* + * 0x2e is reserved and should not be used in input drivers. + * It was used by HID as ABS_MISC+6 and userspace needs to detect if + * the next ABS_* event is correct or is just ABS_MISC + n. + * We define here ABS_RESERVED so userspace can rely on it and detect + * the situation described above. + */ +#define ABS_RESERVED 0x2e + #define ABS_MT_SLOT 0x2f /* MT slot being modified */ #define ABS_MT_TOUCH_MAJOR 0x30 /* Major axis of touching ellipse */ #define ABS_MT_TOUCH_MINOR 0x31 /* Minor axis (omit if circular) */ |