drmmode_output_dpms is called especially with !output->crtc found in
xf86DisableUnusedFunctions so we have to guard for it, else the server
segfaults:
0 0x00007fdc1706054b in drmmode_output_dpms (output=0x55e15243c210, mode=3) at
drmmode_display.c:2243
1 0x000055e1500b6873 in xf86DisableUnusedFunctions (pScrn=0x55e152133f00) at
xf86Crtc.c:3021
2 0x000055e1500be940 in xf86RandR12CrtcSet (pScreen=<optimized out>,
randr_crtc=0x55e1524b2b90, randr_mode=0x0, x=0, y=0, rotation=<optimized out>,
num_randr_outputs=0, randr_outputs=0x0) at xf86RandR12.c:1244
3 0x000055e1500fa1c2 in RRCrtcSet (crtc=<optimized out>, mode=0x0, x=0, y=0,
rotation=rotation@entry=1, numOutputs=numOutputs@entry=0, outputs=0x0) at
rrcrtc.c:763
4 0x000055e1500fba9e in ProcRRSetCrtcConfig (client=0x55e152bfae50) at
rrcrtc.c:1390
5 0x000055e150044008 in Dispatch () at dispatch.c:478
6 0x000055e150047ff8 in dix_main (argc=13, argv=0x7ffc68561038,
envp=<optimized out>) at main.c:276
7 0x00007fdc1a0c6a87 in __libc_start_main () at /lib64/libc.so.6
8 0x000055e150031d0a in _start () at ../sysdeps/x86_64/start.S:120
Fixes: ba0c75177 ("modesetting: Fix up some XXX from removing GLAMOR_HAS_DRM_*")
Signed-off-by: Tobias Klausmann <tobias.johannes.klausmann@mni.thm.de>
Reviewed-by: Adam Jackson <ajax@redhat.com>
1c002bc434