Booting Fedora Design Suite 22 Beta TC6 from USB led to unexpected crash related to x session on ASUS X550ZE. From the dmesg attached on the bug report:

[ 9.253707] [drm:radeon_acpi_init [radeon]] *ERROR* Cannot find a backlight controller

From journalctl, here are highlights:

Mar 31 13:15:01 localhost kernel: No NUMA configuration found

Mar 31 13:15:01 localhost kernel: ACPI Exception: AE_NOT_FOUND, While evaluating Sleep State [_S1_] (20150204/hwxface-580) Mar 31 13:15:01 localhost kernel: ACPI Exception: AE_NOT_FOUND, While evaluating Sleep State [_S2_] (20150204/hwxface-580) ... Mar 31 13:15:08 localhost kernel: [drm] Radeon Display Connectors Mar 31 13:15:08 localhost kernel: radeon 0000:01:00.0: No connectors reported connected with modes ... Mar 31 13:15:35 localhost rngd[1135]: No entropy sources working, exiting rngd Mar 31 13:15:35 localhost mcelog[1131]: AMD Processor family 21: Please use the edac_mce_amd module instead. : Success Mar 31 13:15:35 localhost mcelog.setup[1130]: CPU is unsupported ... Mar 31 13:16:01 localhost /usr/libexec/gdm-x-session[1650]: (II) The server relies on udev to provide the list of input devices. Mar 31 13:16:01 localhost /usr/libexec/gdm-x-session[1650]: If no devices become available, reconfigure udev or disable AutoAddDevices. Mar 31 13:16:01 localhost /usr/libexec/gdm-x-session[1650]: (II) Loader magic: 0x81ade0 Mar 31 13:16:01 localhost /usr/libexec/gdm-x-session[1650]: (II) Module ABI versions: Mar 31 13:16:01 localhost /usr/libexec/gdm-x-session[1650]: X.Org ANSI C Emulation: 0.4 Mar 31 13:16:01 localhost /usr/libexec/gdm-x-session[1650]: X.Org Video Driver: 19.0 Mar 31 13:16:01 localhost /usr/libexec/gdm-x-session[1650]: X.Org XInput driver : 21.0 Mar 31 13:16:01 localhost /usr/libexec/gdm-x-session[1650]: X.Org Server Extension : 9.0 Mar 31 13:16:01 localhost /usr/libexec/gdm-x-session[1650]: (II) systemd-logind: took control of session /org/freedesktop/login1/session/_31 Mar 31 13:16:01 localhost /usr/libexec/gdm-x-session[1650]: (II) xfree86: Adding drm device (/dev/dri/card0) Mar 31 13:16:01 localhost /usr/libexec/gdm-x-session[1650]: (II) systemd-logind: got fd for /dev/dri/card0 226:0 fd 9 paused 0 Mar 31 13:16:01 localhost /usr/libexec/gdm-x-session[1650]: (II) xfree86: Adding drm device (/dev/dri/card1) Mar 31 13:16:01 localhost kernel: [drm] probing gen 2 caps for device 1022:1425 = 733d01/e Mar 31 13:16:01 localhost kernel: [drm] enabling PCIE gen 3 link speeds, disable with radeon.pcie_gen2=0 Mar 31 13:16:02 localhost /usr/libexec/gdm-x-session[1650]: (EE) systemd-logind: failed to take device /dev/dri/card1: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken. ... Mar 31 13:16:03 localhost /usr/libexec/gdm-x-session[1650]: (EE) /dev/dri/card1: failed to set DRM interface version 1.4: Permission denied Mar 31 13:16:03 localhost /usr/libexec/gdm-x-session[1650]: (--) PCI:*(0:0:1:0) 1002:130d:1043:222d rev 0, Mem @ 0xb0000000/268435456, 0xd0000000/8388608, 0xfeb00000/262144, I/O @ 0x0000f000/256, BIOS @ 0x????????/131072 Mar 31 13:16:03 localhost /usr/libexec/gdm-x-session[1650]: (--) PCI: (0:1:0:0) 1002:6665:1043:130d rev 0, Mem @ 0xc0000000/268435456, 0xfea00000/262144, I/O @ 0x0000e000/256, BIOS @ 0x????????/131072 ... Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) Backtrace: Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) 0: /usr/libexec/Xorg (OsLookupColor+0x139) [0x599dd9] Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) 1: /lib64/libc.so.6 (__restore_rt+0x0) [0x7fb0c2284b1f] Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) 2: /lib64/libc.so.6 (__GI___strcmp_ssse3+0x16) [0x7fb0c23983d6] Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) 3: /usr/libexec/Xorg (xf86SIGIOSupported+0xa18) [0x4a36b8] Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) 4: /lib64/libdbus-1.so.3 (dbus_connection_dispatch+0x375) [0x7fb0c44a8095] Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) 5: /lib64/libdbus-1.so.3 (dbus_connection_dispatch+0x64d) [0x7fb0c44a891d] Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) 6: /usr/libexec/Xorg (config_fini+0x4c1) [0x49d7b1] Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) 7: /usr/libexec/Xorg (WakeupHandler+0x6d) [0x43ed3d] Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) 8: /usr/libexec/Xorg (WaitForSomething+0x1e7) [0x592ea7] Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) 9: /usr/libexec/Xorg (SendErrorToClient+0x111) [0x439f81] Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) 10: /usr/libexec/Xorg (remove_fs_handlers+0x41b) [0x43e26b] Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) 11: /lib64/libc.so.6 (__libc_start_main+0xf0) [0x7fb0c2270790] Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) 12: /usr/libexec/Xorg (_start+0x29) [0x428659] Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) 13: ? (?+0x29) [0x29] Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) Segmentation fault at address 0x0 Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: Fatal server error: Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) Caught signal 11 (Segmentation fault). Server aborting Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: Please consult the Fedora Project support Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: at http://wiki.x.org Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: for help. Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information. Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE) Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (II) AIGLX: Suspending AIGLX clients for VT switch Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: xrdb: Connection refused Mar 31 13:16:27 localhost Xorg[1652]: <audit-1701> auid=1000 uid=1000 gid=1000 ses=1 subj=unconfined_u:unconfined_r:xserver_t:s0-s0:c0.c1023 pid=1652 comm="Xorg" exe="/usr/libexec/Xorg" sig=6 Mar 31 13:16:27 localhost /usr/libexec/gdm-x-session[1650]: (EE)xrdb: Can't open display ':0'

As a result, I am unable to fully run Gnome X Session due to these unexpected issue and can only use Gnome on Wayland with known issues such as lack of Touchpad and Hotkey support (it seems libinput has currently no effect despite detecting Elantech Touchpad within the laptop and Hotkeys). I don't know if other ASUS X550 family equiped with AMD APU shares similar result.

Laptop used for the test: ASUS X550ZE (http://www.asus.com/Notebooks_Ultrabooks/X550ZE/specifications/)

Bug report: https://bugzilla.redhat.com/show_bug.cgi?id=1206733

I attached the journal if needed but most files are included in the bug report. It would be nice to improve the experience for AMD APU laptop before the final release now that test day Radeon has become a distant past.