last "zypper update" broke my xfce4 setup -- I can't login anymore!

.xsession-errors shows:

$ cat .xsession-errors.old
xrdb:  "Xft.hinting" on line 9 overrides entry on line 6
xrdb:  "Xft.hintstyle" on line 11 overrides entry on line 7
Failed to issue method call: Access denied
Failed to inhibit: Unknown error -1


login with fvwm2 still works.  trying "startxfce4" shows the same error message, strace shows that this command fails:

$ systemd-inhibit "--what=idle:handle-power-key:handle-suspend-key:handle-hibernate-key:handle-lid-switch" "xfce4-session"
Failed to issue method call: Access denied
Failed to inhibit: Unknown error -1


$ strace -s99 -fv startxfce4 
...
[pid  2837] execve("/usr/bin/systemd-inhibit", ["systemd-inhibit", "--what=idle:handle-power-key:handle-suspend-key:handle-hibernate-key:handle-lid-switch", "xfce4-session"], ["LESSKEY=/etc/lesskey.bin", "XDG_VTNR=7", ...]) = 0
...
[pid  2837] sendto(3, "BEGIN\r\n", 7, MSG_NOSIGNAL, NULL, 0) = 7
[pid  2837] poll([{fd=3, events=POLLIN|POLLOUT}], 1, 4294967295) = 1 ([{fd=3, revents=POLLOUT}])
[pid  2837] sendmsg(3, {msg_name(0)=NULL, msg_iov(2)=[{"l\1\0\1\0\0\0\0\1\0\0\0n\0\0\0\1\1o\0\25\0\0\0/org/freedesktop/DBus\0\0\0\6\1s\0\24\0\0\0org.freedesktop.DBus\0\0\0\0\2\1s\0\24\0\0\0org.freedes"..., 128}, {"", 0}], msg_controllen=0, msg_flags=0}, MSG_NOSIGNAL) = 128
[pid  2837] poll([{fd=3, events=POLLIN}], 1, 25000) = 1 ([{fd=3, revents=POLLIN}])
[pid  2837] recvmsg(3, {msg_name(0)=NULL, msg_iov(1)=[{"l\2\1\1\n\0\0\0\1\0\0\0=\0\0\0\6\1s\0\5\0\0\0:1.60\0\0\0\5\1u\0\1\0\0\0\10\1g\0\1s\0\0\7\1s\0\24\0\0\0org.freedesktop.DBus\0\0\0\0\5\0\0\0:1.60\0l\4\1\1\n\0\0\0\2"..., 2048}], msg_controllen=0, msg_flags=MSG_CMSG_CLOEXEC}, MSG_CMSG_CLOEXEC) = 260
[pid  2837] recvmsg(3, 0x7fff9d636130, MSG_CMSG_CLOEXEC) = -1 EAGAIN (Resource temporarily unavailable)
[pid  2837] sendmsg(3, {msg_name(0)=NULL, msg_iov(2)=[{"l\1\0\1\206\0\0\0\2\0\0\0\202\0\0\0\1\1o\0\27\0\0\0/org/freedesktop/login1\0\6\1s\0\26\0\0\0org.freedesktop.login1\0\0\2\1s\0\36\0\0\0org.freedes"..., 152}, {"O\0\0\0idle:handle-power-key:handle-suspend-key:handle-hibernate-key:handle-lid-switch\0\r\0\0\0xfce4-sessi"..., 134}], msg_controllen=0, msg_flags=0}, MSG_NOSIGNAL) = 286
[pid  2837] poll([{fd=3, events=POLLIN}], 1, 25000) = 1 ([{fd=3, revents=POLLIN}])
[pid  2837] recvmsg(3, {msg_name(0)=NULL, msg_iov(1)=[{"l\3\1\1\34\0\0\0Z\0\0\0]\0\0\0\6\1s\0\5\0\0\0:1.60\0\0\0\4\1s\0'\0\0\0org.freedesktop.DBus.Error.AccessDenied\0\5\1u\0\2\0\0\0\10\1g\0\1s\0\0\7\1s"..., 2048}], msg_controllen=0, msg_flags=MSG_CMSG_CLOEXEC}, MSG_CMSG_CLOEXEC) = 140
[pid  2837] recvmsg(3, 0x7fff9d6360d0, MSG_CMSG_CLOEXEC) = -1 EAGAIN (Resource temporarily unavailable)
[pid  2837] writev(2, [{"Failed to issue method call: Access denied", 42}, {"\n", 1}], 2Failed to issue method call: Access denied
) = 43
[pid  2837] writev(2, [{"Failed to inhibit: Unknown error -1", 35}, {"\n", 1}], 2Failed to inhibit: Unknown error -1
) = 36
[pid  2837] close(3)                    = 0
[pid  2837] exit_group(1)               = ?
[pid  2837] +++ exited with 1 +++
<... wait4 resumed> [{WIFEXITED(s) && WEXITSTATUS(s) == 1}], 0, NULL) = 2837
rt_sigaction(SIGINT, {SIG_DFL, [], SA_RESTORER|SA_RESTART, 0x7ff19ee6f450}, {0x426a63, [], SA_RESTORER|SA_RESTART, 0x7ff19ee6f450}, 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
--- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=2837, si_status=1, si_utime=0, si_stime=0} ---
wait4(-1, 0x7fffeae12f98, WNOHANG, NULL) = -1 ECHILD (No child processes)
rt_sigreturn()                          = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
read(255, "", 3219)                     = 0
exit_group(1)                           = ?
+++ exited with 1 +++



please help!!!