SDDM gamma set abort

On an Dell XPS 7390 Xserver master fails since 245b9db0 with:

#0  0x00007f995d56f615 in raise () from /usr/lib/libc.so.6
#1  0x00007f995d558862 in abort () from /usr/lib/libc.so.6
#2  0x000055b3fe25b99a in OsAbort () at ../../src/xserver/os/utils.c:1327
#3  0x000055b3fe2610a3 in AbortServer () at ../../src/xserver/os/log.c:886
#4  0x000055b3fe261e76 in FatalError (f=f@entry=0x55b3fe2e9410 "Caught signal %d (%s). Server aborting\n") at ../../src/xserver/os/log.c:1024
#5  0x000055b3fe258f1c in OsSigHandler (unused=<optimized out>, sip=0x7ffcb0750e30, signo=11) at ../../src/xserver/os/osinit.c:156
#6  OsSigHandler (signo=11, sip=0x7ffcb0750e30, unused=<optimized out>) at ../../src/xserver/os/osinit.c:110
#7  <signal handler called>
#8  0x00007f995d697ad3 in __memmove_avx_unaligned_erms () from /usr/lib/libc.so.6
#9  0x000055b3fe2a7ebd in xf86RandR12CrtcSetGamma (pScreen=<optimized out>, randr_crtc=0x55b3ff2ef160) at ../../src/xserver/hw/xfree86/modes/xf86RandR12.c:1369
#10 0x000055b3fe2a6f80 in xf86RandR12CrtcInitGamma (crtc=crtc@entry=0x55b3fed79180, gamma_red=gamma_red@entry=1, gamma_green=gamma_green@entry=1, gamma_blue=gamma_blue@entry=1)
    at ../../src/xserver/hw/xfree86/modes/xf86RandR12.c:1423
#11 0x000055b3fe2a9c5b in xf86RandR12InitGamma (pScrn=pScrn@entry=0x55b3febf8ad0, gammaSize=gammaSize@entry=256) at ../../src/xserver/hw/xfree86/modes/xf86RandR12.c:1484
#12 0x000055b3fe2aa2ba in xf86RandR12Init12 (pScreen=0x55b3fed85d00) at ../../src/xserver/hw/xfree86/modes/xf86RandR12.c:2382
#13 xf86RandR12Init (pScreen=pScreen@entry=0x55b3fed85d00) at ../../src/xserver/hw/xfree86/modes/xf86RandR12.c:893
#14 0x000055b3fe29cf8b in xf86CrtcScreenInit (screen=screen@entry=0x55b3fed85d00) at ../../src/xserver/hw/xfree86/modes/xf86Crtc.c:822
#15 0x00007f995db4b3d6 in ScreenInit (pScreen=0x55b3fed85d00, argc=<optimized out>, argv=<optimized out>) at ../../src/xserver/hw/xfree86/drivers/modesetting/driver.c:1896
#16 0x000055b3fe188167 in AddScreen (pfnInit=pfnInit@entry=0x55b3fe274780 <xf86ScreenInit>, argc=argc@entry=13, argv=argv@entry=0x7ffcb0751d88) at ../../src/xserver/dix/dispatch.c:3932
#17 0x000055b3fe2761c5 in InitOutput (pScreenInfo=pScreenInfo@entry=0x55b3fe382800 <screenInfo>, argc=argc@entry=13, argv=argv@entry=0x7ffcb0751d88)
    at ../../src/xserver/hw/xfree86/common/xf86Init.c:632
#18 0x000055b3fe18bd9c in dix_main (argc=13, argv=0x7ffcb0751d88, envp=<optimized out>) at ../../src/xserver/dix/main.c:190
#19 0x00007f995d55a152 in __libc_start_main () from /usr/lib/libc.so.6
#20 0x000055b3fe14e84e in _start ()