UDL & Modeset with Mesa 13.0.1 - Segmentation fault

[poma]

Airlie solved everything concerning the kernel,
so it seems, now it's user space turn.

= mesa-libgbm-12.0.3 - works OK
...
[   714.429] (II) Loading sub module "glamoregl"
[   714.429] (II) LoadModule: "glamoregl"
[   714.430] (II) Loading /usr/lib64/xorg/modules/libglamoregl.so
[   714.480] (II) Module glamoregl: vendor="X.Org Foundation"
[   714.481] 	compiled for 1.19.0, module version = 1.0.0
[   714.481] 	ABI class: X.Org ANSI C Emulation, version 0.4
...
[   714.481] (II) glamor: OpenGL accelerated X.org driver based.
[   714.633] (II) glamor: EGL version 1.4 (DRI2):
[   714.633] EGL_MESA_drm_image required.
[   714.634] (EE) modeset(0): glamor initialization failed
[   714.634] (II) modeset(0): ShadowFB: preferred NO, enabled NO
...
[   714.643] (==) Depth 24 pixmap format is 32 bpp
[   714.645] (==) modeset(0): Backing store enabled
[   714.645] (==) modeset(0): Silken mouse enabled
[   714.645] (II) modeset(0): RandR 1.2 enabled, ignore the following RandR disabled message.
[   714.646] (==) modeset(0): DPMS enabled
[   714.646] (--) RandR disabled
[   714.669] (II) AIGLX: Screen 0 is not DRI2 capable
[   714.669] (EE) AIGLX: reverting to software rendering
[   714.683] (II) IGLX: enabled GLX_MESA_copy_sub_buffer
[   714.686] (II) IGLX: Loaded and initialized swrast
[   714.686] (II) GLX: Initialized DRISWRAST GL provider for screen 0
[   714.691] (II) modeset(0): Damage tracking initialized
...

= mesa-libgbm-13.0.1 - not quite
...
[  2324.953] (II) Loading sub module "glamoregl"
[  2324.953] (II) LoadModule: "glamoregl"
[  2324.953] (II) Loading /usr/lib64/xorg/modules/libglamoregl.so
[  2325.000] (II) Module glamoregl: vendor="X.Org Foundation"
[  2325.000] 	compiled for 1.19.0, module version = 1.0.0
[  2325.000] 	ABI class: X.Org ANSI C Emulation, version 0.4
...
[  2325.001] (II) glamor: OpenGL accelerated X.org driver based.
[  2325.002] (EE) 
[  2325.002] (EE) Backtrace:
[  2325.006] (EE) 0: /usr/libexec/Xorg (OsLookupColor+0x139) [0x59e389]
[  2325.008] (EE) 1: /lib64/libpthread.so.0 (__restore_rt+0x0) [0x7f69d836ac2f]
[  2325.009] (EE) 2: /lib64/libgbm.so.1 (gbm_surface_has_free_buffers+0x1505) [0x7f69d2b64685]
[  2325.010] (EE) 3: /lib64/libgbm.so.1 (gbm_surface_has_free_buffers+0x1b98) [0x7f69d2b653b8]
[  2325.011] (EE) 4: /lib64/libgbm.so.1 (gbm_surface_has_free_buffers+0x1498) [0x7f69d2b644c8]
[  2325.012] (EE) 5: /lib64/libgbm.so.1 (gbm_create_device+0x4c) [0x7f69d2b61a4c]
[  2325.014] (EE) 6: /usr/lib64/xorg/modules/libglamoregl.so (glamor_egl_init+0x83) [0x7f69d2d73fb3]
[  2325.015] (EE) 7: /usr/lib64/xorg/modules/drivers/modesetting_drv.so (_init+0x4d21) [0x7f69d2facfd1]
[  2325.016] (EE) 8: /usr/libexec/Xorg (InitOutput+0xa82) [0x47d6c2]
[  2325.017] (EE) 9: /usr/libexec/Xorg (InitFonts+0x216) [0x43ae36]
[  2325.020] (EE) 10: /lib64/libc.so.6 (__libc_start_main+0xf1) [0x7f69d7fb8731]
[  2325.022] (EE) 11: /usr/libexec/Xorg (_start+0x29) [0x424d29]
[  2325.024] (EE) 12: ? (?+0x29) [0x29]
[  2325.025] (EE) 
[  2325.025] (EE) Segmentation fault at address 0xc
[  2325.025] (EE) 
Fatal server error:
[  2325.025] (EE) Caught signal 11 (Segmentation fault). Server aborting
[  2325.026] (EE) 
[  2325.026] (EE) 
...
[  2325.027] (EE) Server terminated with error (1). Closing log file.


A call to not load the module(s) is not at all useful:
Section "Module"
    Disable  "glx"
    Disable  "glamoregl"
EndSection

...
(WW) "glx" will not be loaded unless you've specified it to be loaded elsewhere.
(WW) "glamoregl" will not be loaded unless you've specified it to be loaded elsewhere.
(II) "glx" will be loaded even though the default is to disable it.
...
(II) Loading sub module "glamoregl"
(II) LoadModule: "glamoregl"
(II) Loading /usr/lib64/xorg/modules/libglamoregl.so
(II) Module glamoregl: vendor="X.Org Foundation"
	compiled for 1.19.0, module version = 1.0.0
	ABI class: X.Org ANSI C Emulation, version 0.4
(II) glamor: OpenGL accelerated X.org driver based.
(EE) 
(EE) Backtrace:
...

Therefore, until the issue resolved, there remain two workarounds:
downgrade mesa to 12.0.3, what works
OR
leave mesa 13.0.1 and:
# rm /usr/lib64/xorg/modules/libglamoregl.so


Trick or treat