Graphics acceleration in PcbNew causes segfault on Wayland

[Dylan Mackenzie]

Application: kicad
Version: (5.0.0-rc1), release build
Libraries:
    wxWidgets 3.0.3
    libcurl/7.55.1 OpenSSL/1.1.0g zlib/1.2.11 libidn2/2.0.4 libpsl/0.18.0 (+libidn2/2.0.3) libssh2/1.8.0 nghttp2/1.25.0
Platform: Linux 4.15.6-300.fc27.x86_64 x86_64, 64 bit, Little endian, wxGTK
Build Info:
    wxWidgets: 3.0.3 (wchar_t,wx containers,compatible with 2.8) GTK+ 3.22
    Boost: 1.64.0
    Curl: 7.55.1
    Compiler: GCC 7.3.1 with C++ ABI 1011

Build settings:
    USE_WX_GRAPHICS_CONTEXT=ON
    USE_WX_OVERLAY=OFF
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=ON
    KICAD_SCRIPTING_WXPYTHON=ON
    KICAD_SCRIPTING_ACTION_MENU=OFF
    BUILD_GITHUB_PLUGIN=ON
    KICAD_USE_OCE=ON
    KICAD_SPICE=ON

When attempting to enable graphics acceleration mode while on Wayland, PcbNew segfaults with the attached coredump.

The segfault is triggered when `XQueryExtension` invokes the `LockDisplay` macro, which attempts to dereference `Display->lock_fns`. However, the underlying issue is that wxGLCanvas doesn't support Wayland.

The issue is discussed in further detail https://trac.wxwidgets.org/ticket/17702.

Obviously, Wayland support in wxWidgets would be ideal, but in the meantime it might be a good idea to disable accelerated graphics mode when not running on X.

[Maciej Suminski (orsonmmz)]

I have just tried out KiCad on Wayland. I confirm that the accelerated rendering backend does not work, as Wayland does not support GLX, but I do not see a crash either (weston 3.0.0-2 + wayland 1.14.0-1).

[Dylan Mackenzie (ecstaticmorse)]

I'm on mutter 3.26.2-2 + wayland 1.14.01 (the default setup on fedora), so perhaps the issue is the compositor? I don't know much about X/wayland, so I won't be very helpful in pinpointing the issue. X's Display struct isn't being properly initialized (lock_fns points to invalid memory), but I'm not sure who's responsibility that is. Let me know if I can do anything to elucidate the problem.

[Maciej Suminski (orsonmmz)]

I just tried mutter-3.26.2 and it behaves the same. I suspect wxWidgets makes the difference - I noticed it is built against GTK3, which has given us some headache already.

[Tomasz Wlostowski (twlostow)]

Jon, why do you consider a bug in Wayland a critical bug in Kicad?

Tom

[Jon Evans (craftyjon)]

I just wanted to flag it as critical so we remember to resolve it somehow, since the user has reported a crash. Maybe the action is just to mention this in the release notes so that users know what to expect.

[Jon Evans (craftyjon)]

Proposing a docs change to address this:
https://github.com/KiCad/kicad-website/pull/276