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-rw-r--r--src/plugins/platforms/xcb/README10
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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
@@ -21,3 +21,13 @@ REDUCING RUNTIME DEPENDENCIES
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.
+
+PACKAGE VERSION REQUIREMENTS
+
+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 http://lists.x.org/archives/xorg-devel/2014-July/043059.html 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.