X-Server problem on ASI MB-4D50AG

Problem:
Switching to X-Server graphic mode on ASI MB-4D50AG under Linux leads to segmentation fault.
Screen stays completely dark.

symptom 1:
rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
rt_sigaction(SIGCHLD, NULL, {SIG_DFL}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
nanosleep({1, 0}, {1, 0}) = 0
ioctl(3, KDSETMODE <unfinished ...>
+++ killed by SIGSEGV +++

symptom 2:
Screen saver for text console freezes PC

Solution:
Deactivate screen saver for text console.
setterm -blank 0