fdo-mirrors/libinput
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/libinput/libinput.git synced 2026-01-09 00:30:15 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions

doc/user: update the timer offset warning for the new "too slow" message

Browse source 
Related #533

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
(cherry picked from commit 11d517f969)
This commit is contained in:
Peter Hutterer 2020-10-22 15:10:38 +10:00
parent 1e547e2baa
commit e84dfbb731
1 changed files with 14 additions and 14 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

28
doc/user/faqs.rst
View file

@ -287,28 +287,28 @@ details on the hwdb and how to modify it locally.
.. _faq_timer_offset:
------------------------------------------------------------------------------
What causes the "timer offset negative" warning?
What causes the "your system is too slow" warning?
------------------------------------------------------------------------------
libinput relies on the caller to call **libinput_dispatch()** whenever data is
available on the epoll-fd. Doing so will process the state of all devices
and can trigger some timers to be set (e.g. palm detection, tap-to-click,
disable-while-typing, etc.). Internally, libinput's time offsets are always
based on the event time of the triggering event.
available. **libinput_dispatch()** will process the state of all devices,
including some time-sensitive features (e.g. palm detection, tap-to-click,
disable-while-typing, etc.).
For example, a touch event with time T may trigger a timer for the time T +
180ms. When setting a timer, libinput checks the wall clock time to ensure
that this time T + offset is still in the future. If not, the warning is
logged.
If the time between the event and the call to **libinput_dispatch()**
is excessive, those features may not work correctly. For example, a delay in
touch event processing may cause wrong or missing tap-to-click events or
a palm may not be detected correctly.
When this warning appears, it simply means that too much time has passed
between the event occurring (and the epoll-fd triggering) and the current
time. In almost all cases this is an indication of the caller being
overloaded and not handling events as speedily as required.
between the event occurring and the current time. In almost all cases this
is an indication of the caller being overloaded and not handling events as
speedily as required.
The warning has no immediate effect on libinput's behavior but some of the
functionality that relies on the timer may be impeded (e.g. palms are not
detected as they should be).
functionality that relies on the timer may be impeded. This is not a bug in
libinput. libinput does not control how quickly **libinput_dispatch()** is
called.
.. _faq_wayland: