path: root/src/plugins/platforms/xcb/README
diff options
authorLaszlo Agocs <>2016-10-07 14:56:29 +0200
committerOswald Buddenhagen <>2016-10-10 16:59:32 +0000
commit0a71cc111ae92cdae604fdb1d4ce0090f1fb6a20 (patch)
tree0979be73d5b427ac5eae34b733fda404f99f8e38 /src/plugins/platforms/xcb/README
parentb4085e56b9040247393b279f64b8cd63af863798 (diff)
xcb: Drop libXi version check
...because we cannot support it in a robust way. Querying the version via pkg-config only works when xi2 is picked up via pkg-config. Also, having a version at build time does not mean we'll have the same at runtime. Modern distros (e.g. Ubuntu 15.04 and newer) will have libXi 1.7.4 or newer. Task-number: QTBUG-56017 Change-Id: Ia4a3b0dc47f2b92bcc953f462c95602a8ea2efd6 Reviewed-by: Gatis Paeglis <> Reviewed-by: Lars Knoll <>
Diffstat (limited to 'src/plugins/platforms/xcb/README')
1 files changed, 10 insertions, 0 deletions
diff --git a/src/plugins/platforms/xcb/README b/src/plugins/platforms/xcb/README
index 15cf4cf241..5efc9b7f99 100644
--- a/src/plugins/platforms/xcb/README
+++ b/src/plugins/platforms/xcb/README
The '-qt-xcb' configure option can be used to get rid of most xcb- dependencies. Only libxcb will
still be linked dynamically, since it will be most likely be pulled in via other dependencies anyway.
This should allow for binaries that are portable across most modern Linux distributions.
+When using touch input via XInput 2.2 or higher, there is a potential issue on systems that ship with
+a libXi older than 1.7.4. This is because XIAllowTouchEvents can deadlock with libXi 1.7.3 and earlier.
+When touch events are never received, this is not an issue, so plain mouse/keyboard systems are not affected.
+See for details on the libXi patch.
+Qt versions before 5.8 attempted to recognize this scenario based on the pkg-config package version and skip
+the call. This has been removed starting from 5.8 since relying on pkg-config package versions is unsafe given
+that Qt must also support systems with limited or incomplete pkg-config setups.