When `MESA_LOADER_DRIVER_OVERRIDE` is set to `zink` and the display
initialization fails, fallback to software rendering.
The error was reported in #10123 and it can be reproduced with:
$ MESA_LOADER_DRIVER_OVERRIDE=zink eglinfo
`eglinfo` would crash in `dri2_display_release()` because of
`assert(dri2_dpy->ref_count > 0)`.
After bisecting the error to commit 8cd44b8843 ("egl/glx: add
autoloading for zink"), I found out that, before this change, the
display was set to initialized even when `_eglDriver.Initialize(disp)`
failed:
disp->Options.Zink = env && !strcmp(env, "zink");
// disp->Options.Zink is true
if (!_eglDriver.Initialize(disp)) {
[...]
// Zink initialization has failed at this point
// However, success is set to true:
bool success = disp->Options.Zink;
if (!disp->Options.Zink && !getenv("GALLIUM_DRIVER")) {
[...]
}
// Software initialization is ignored because success is true
if (!success) {
[...]
}
}
// The display is set as initialized even though it shouldn't
disp->Initialized = EGL_TRUE;
Resolves: https://gitlab.freedesktop.org/mesa/mesa/-/issues/10123
Fixes: 8cd44b8843 ("egl/glx: add autoloading for zink")
Signed-off-by: José Expósito <jexposit@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26184>
d913927fe9