$ lspci
00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09)
00:01.0 PCI bridge: Intel Corporation Xeon E3-1200/2nd Generation Core Processor Family PCI Express Root Port (rev 09)
00:16.0 Communication controller: Intel Corporation 6 Series/C200 Series Chipset Family MEI Controller #1 (rev 04)
00:19.0 Ethernet controller: Intel Corporation 82579V Gigabit Network Connection (rev 05)
00:1a.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 (rev 05)
00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 05)
00:1c.0 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 1 (rev b5)
00:1c.1 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 2 (rev b5)
00:1c.3 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 4 (rev b5)
00:1c.4 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 5 (rev b5)
00:1c.6 PCI bridge: Intel Corporation 82801 PCI Bridge (rev b5)
00:1d.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 (rev 05)
00:1f.0 ISA bridge: Intel Corporation Z68 Express Chipset Family LPC Controller (rev 05)
00:1f.2 SATA controller: Intel Corporation 6 Series/C200 Series Chipset Family SATA AHCI Controller (rev 05)
00:1f.3 SMBus: Intel Corporation 6 Series/C200 Series Chipset Family SMBus Controller (rev 05)
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Barts XT [Radeon HD 6870]
01:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Barts HDMI Audio [Radeon HD 6800 Series]
03:00.0 USB controller: ASMedia Technology Inc. ASM1042 SuperSpeed USB Host Controller
04:00.0 SATA controller: JMicron Technology Corp. JMB362 SATA Controller (rev 10)
05:00.0 USB controller: ASMedia Technology Inc. ASM1042 SuperSpeed USB Host Controller
06:00.0 PCI bridge: ASMedia Technology Inc. ASM1083/1085 PCIe to PCI Bridge (rev 01)

$ uname -a # Problems
Linux localhost 3.17.4-1-ARCH #1 SMP PREEMPT Thu Oct 30 20:45:16 CET 2014 x86_64 GNU/Linux

$ uname -a # Working
Linux localhost 3.17.2-1-ARCH #1 SMP PREEMPT Thu Oct 30 20:49:39 CET 2014 x86_64 GNU/Linux


$ pacman -Q mesa mesa-dri
mesa 10.3.4-1
mesa-dri 10.3.4-1


$ journalctl -x
...
Dec 01 10:25:40 localhost kernel: BUG: unable to handle kernel paging request at ffffec2000000900
Dec 01 10:25:40 localhost kernel: IP: [<ffffffff811ac636>] kfree+0x56/0x1a0
Dec 01 10:25:40 localhost kernel: PGD 0 
Dec 01 10:25:40 localhost kernel: Oops: 0000 [#1] PREEMPT SMP 
Dec 01 10:25:40 localhost kernel: Modules linked in: ebtable_broute bridge stp llc ebtable_filter ebtable_nat ebtables ip6table_mangle ip6table_raw ip6table_filter ip6table_nat nf_conntrack_ipv6 nf_defrag
Dec 01 10:25:40 localhost kernel:  glue_helper ablk_helper cryptd psmouse serio_raw pcspkr snd_hda_intel snd_hda_controller e1000e snd_hda_codec fan thermal snd_hwdep snd_pcm ptp mei_me pps_core snd_timer
Dec 01 10:25:40 localhost kernel: CPU: 0 PID: 455 Comm: Xorg.bin Not tainted 3.17.4-1-ARCH #1
Dec 01 10:25:40 localhost kernel: Hardware name: System manufacturer System Product Name/P8Z68-V, BIOS 3603 11/09/2012
Dec 01 10:25:40 localhost kernel: task: ffff880406cc5080 ti: ffff8803fde2c000 task.ti: ffff8803fde2c000
Dec 01 10:25:40 localhost kernel: RIP: 0010:[<ffffffff811ac636>]  [<ffffffff811ac636>] kfree+0x56/0x1a0
Dec 01 10:25:40 localhost kernel: RSP: 0018:ffff8803fde2fa30  EFLAGS: 00010286
Dec 01 10:25:40 localhost kernel: RAX: 0000022000000900 RBX: 0000100000024414 RCX: 0000000000010005
Dec 01 10:25:40 localhost kernel: RDX: 000077ff80000000 RSI: 0000000000000005 RDI: 0000100000024414
Dec 01 10:25:40 localhost kernel: RBP: ffff8803fde2fa48 R08: 0000000000000005 R09: ffffec2000000900
Dec 01 10:25:40 localhost kernel: R10: 0000000000000013 R11: 0000000000000000 R12: ffff880406ac4600
Dec 01 10:25:40 localhost kernel: R13: ffffffffa0150f8c R14: 00000000000108f0 R15: 0000000000001800
Dec 01 10:25:40 localhost kernel: FS:  00007f2192ed28c0(0000) GS:ffff88041ec00000(0000) knlGS:0000000000000000
Dec 01 10:25:40 localhost kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Dec 01 10:25:40 localhost kernel: CR2: ffffec2000000900 CR3: 000000003701d000 CR4: 00000000000407f0
Dec 01 10:25:40 localhost kernel: Stack:
Dec 01 10:25:40 localhost kernel:  ffff880406640000 ffff880406ac4600 ffff880406640000 ffff8803fde2fb30
Dec 01 10:25:40 localhost kernel:  ffffffffa0150f8c 000000000000004c 000108480001092c ffff880300000008
Dec 01 10:25:40 localhost kernel:  0000ffff00010844 000000000001092c 0000000000010848 0000000000010844
Dec 01 10:25:40 localhost kernel: Call Trace:
Dec 01 10:25:40 localhost kernel:  [<ffffffffa0150f8c>] evergreen_hdmi_setmode+0xd8c/0x1970 [radeon]
Dec 01 10:25:40 localhost kernel:  [<ffffffffa00718d4>] ? drm_detect_hdmi_monitor+0x74/0xc0 [drm]
Dec 01 10:25:40 localhost kernel:  [<ffffffffa0159488>] radeon_atom_encoder_mode_set+0x178/0x3c0 [radeon]
Dec 01 10:25:40 localhost kernel:  [<ffffffffa009a986>] drm_crtc_helper_set_mode+0x356/0x530 [drm_kms_helper]
Dec 01 10:25:40 localhost kernel:  [<ffffffffa00f397c>] radeon_property_change_mode.isra.1+0x3c/0x40 [radeon]
Dec 01 10:25:40 localhost kernel:  [<ffffffffa00f3b2e>] radeon_connector_set_property+0x1ae/0x3f0 [radeon]
Dec 01 10:25:40 localhost kernel:  [<ffffffffa006e4e2>] drm_mode_obj_set_property_ioctl+0x1b2/0x3a0 [drm]
Dec 01 10:25:40 localhost kernel:  [<ffffffffa006e70f>] drm_mode_connector_property_set_ioctl+0x3f/0x60 [drm]
Dec 01 10:25:40 localhost kernel:  [<ffffffffa005efef>] drm_ioctl+0x1df/0x680 [drm]
Dec 01 10:25:40 localhost kernel:  [<ffffffff8105e9ac>] ? __do_page_fault+0x2ec/0x600
Dec 01 10:25:40 localhost kernel:  [<ffffffffa00cc04c>] radeon_drm_ioctl+0x4c/0x80 [radeon]
Dec 01 10:25:40 localhost kernel:  [<ffffffff811da5f0>] do_vfs_ioctl+0x2d0/0x4b0
Dec 01 10:25:40 localhost kernel:  [<ffffffff811da851>] SyS_ioctl+0x81/0xa0
Dec 01 10:25:40 localhost kernel:  [<ffffffff8153db29>] system_call_fastpath+0x16/0x1b
Dec 01 10:25:40 localhost kernel: Code: 00 00 00 80 ff 77 00 00 49 b9 00 00 00 00 00 ea ff ff 48 01 d8 48 0f 42 15 e8 b9 66 00 48 01 d0 48 c1 e8 0c 48 c1 e0 06 49 01 c1 <49> 8b 01 f6 c4 80 0f 85 0e 01 00 
Dec 01 10:25:40 localhost kernel: RIP  [<ffffffff811ac636>] kfree+0x56/0x1a0
Dec 01 10:25:41 localhost kernel:  RSP <ffff8803fde2fa30>
Dec 01 10:25:41 localhost kernel: CR2: ffffec2000000900
Dec 01 10:25:41 localhost kernel: cfg80211: Calling CRDA to update world regulatory domain
...