Created attachment 75598
Xorg log file

I am not able to logout or shutdown my system, a laptop with hybrid graphics,  without triggering a hard lockup. However, this does only happen if the dedicated AMD GPU is powered off by vgaswitcheroo. Moreover, it might be somehow related to PRIME support being enabled. 

The latest version of xserver-xorg-video-radeon for Ubuntu 13.04 is installed (1:7.1.0-0ubuntu1).

$ lshw -C display
  *-display               
       description: VGA compatible controller
       product: RV710 [Mobility Radeon HD 4300 Series]
       vendor: Advanced Micro Devices [AMD] nee ATI
       physical id: 0
       bus info: pci@0000:01:00.0
       version: 00
       width: 32 bits
       clock: 33MHz
       capabilities: pm pciexpress msi vga_controller bus_master cap_list rom
       configuration: driver=radeon latency=0
       resources: irq:46 memory:d0000000-dfffffff ioport:3000(size=256) memory:f4400000-f440ffff memory:f4420000-f443ffff
  *-display
       description: Display controller
       product: Mobile 4 Series Chipset Integrated Graphics Controller
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 07
       width: 64 bits
       clock: 33MHz
       capabilities: msi pm bus_master cap_list rom
       configuration: driver=i915 latency=0
       resources: irq:45 memory:f0000000-f03fffff memory:e0000000-efffffff ioport:4110(size=8)


Here is syslog output of the bug:
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[  142.230685] BUG: unable to handle kernel NULL pointer dereference at           (null)
[  142.230819] IP: [<ffffffffa01f1ba5>] r600_pcie_gart_tlb_flush+0xf5/0x110 [radeon]
[  142.230977] PGD 0 
[  142.231014] Oops: 0000 [#1] SMP 
[  142.231075] Modules linked in: dm_crypt(F) kvm_intel kvm acer_wmi sparse_keymap snd_hda_codec_realtek xt_hl(F) ip6t_rt(F) snd_hda_intel snd_hda_codec snd_hwdep(F) nf_conntrack_ipv6(F) nf_defrag_ipv6(F) ipt_REJECT(F) microcode(F) xt_LOG(F) snd_pcm(F) xt_limit(F) xt_tcpudp(F) snd_page_alloc(F) xt_addrtype(F) snd_seq_midi(F) snd_seq_midi_event(F) snd_rawmidi(F) arc4(F) psmouse(F) nf_conntrack_ipv4(F) serio_raw(F) nf_defrag_ipv4(F) xt_state(F) iwldvm snd_seq(F) mac80211 ip6table_filter(F) snd_seq_device(F) ip6_tables(F) snd_timer(F) iwlwifi lpc_ich nf_conntrack_netbios_ns(F) nf_conntrack_broadcast(F) nf_nat_ftp(F) nf_nat(F) nf_conntrack_ftp(F) nf_conntrack(F) iptable_filter(F) cfg80211 ip_tables(F) joydev(F) x_tables(F) snd(F) soundcore(F) mac_hid binfmt_misc(F) coretemp lp(F) parport(F) hid_generic usbhid hid radeon i915 i2c_algo_bit ttm drm_kms_helper wmi r8169 ahci(F) drm libahci(F) video(F)
[  142.232175] CPU 0 
[  142.232175] Pid: 1135, comm: Xorg Tainted: GF            3.8.0-7-generic #15-Ubuntu Acer TravelMate 8471/TravelMate 8471
[  142.232175] RIP: 0010:[<ffffffffa01f1ba5>]  [<ffffffffa01f1ba5>] r600_pcie_gart_tlb_flush+0xf5/0x110 [radeon]
[  142.232175] RSP: 0018:ffff88013752bc28  EFLAGS: 00010282
[  142.232175] RAX: ffffc900047a2f34 RBX: 0000000000000000 RCX: 0000000000000000
[  142.232175] RDX: 0000000000000000 RSI: 0000000000002f34 RDI: ffff8801359d6000
[  142.232175] RBP: ffff88013752bc38 R08: 0000000000000000 R09: 0000000000000000
[  142.232175] R10: ffffea0004d3de00 R11: ffffffffa001a448 R12: ffff8801359d6000
[  142.232175] R13: 0000000000000225 R14: 0000000000000225 R15: ffffffffa025d560
[  142.232175] FS:  00007fa8bea89940(0000) GS:ffff88013fc00000(0000) knlGS:0000000000000000
[  142.232175] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  142.232175] CR2: 0000000000000000 CR3: 0000000137882000 CR4: 00000000000407f0
[  142.232175] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  142.232175] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[  142.232175] Process Xorg (pid: 1135, threadinfo ffff88013752a000, task ffff88013750c5c0)
[  142.232175] Stack:
[  142.232175]  ffff8801359d6000 0000000000000225 ffff88013752bc68 ffffffffa01c65d7
[  142.232175]  ffff880134f73080 0000000000000002 ffff8801359d69c0 ffff8801397e2848
[  142.232175]  ffff88013752bc78 ffffffffa01c3baa ffff88013752bc90 ffffffffa0099087
[  142.232175] Call Trace:
[  142.232175]  [<ffffffffa01c65d7>] radeon_gart_unbind+0xa7/0xe0 [radeon]
[  142.232175]  [<ffffffffa01c3baa>] radeon_ttm_backend_unbind+0x1a/0x20 [radeon]
[  142.232175]  [<ffffffffa0099087>] ttm_tt_unbind+0x27/0x40 [ttm]
[  142.232175]  [<ffffffffa0099693>] ttm_bo_cleanup_memtype_use+0x33/0x90 [ttm]
[  142.232175]  [<ffffffffa009a930>] ttm_bo_release+0x210/0x280 [ttm]
[  142.232175]  [<ffffffffa009a9d1>] ttm_bo_unref+0x31/0x40 [ttm]
[  142.232175]  [<ffffffffa01c5407>] radeon_bo_unref+0x47/0x80 [radeon]
[  142.232175]  [<ffffffffa01d7cf9>] radeon_gem_object_free+0x39/0x40 [radeon]
[  142.232175]  [<ffffffffa0010aba>] drm_gem_object_free+0x2a/0x30 [drm]
[  142.232175]  [<ffffffffa00111e8>] drm_gem_handle_delete+0xf8/0x130 [drm]
[  142.232175]  [<ffffffffa0011648>] drm_gem_close_ioctl+0x28/0x30 [drm]
[  142.232175]  [<ffffffffa000f559>] drm_ioctl+0x4e9/0x5b0 [drm]
[  142.232175]  [<ffffffffa0011620>] ? drm_gem_destroy+0x60/0x60 [drm]
[  142.232175]  [<ffffffff8115c14b>] ? unmap_region+0xdb/0x120
[  142.232175]  [<ffffffff8115c453>] ? remove_vma+0x63/0x70
[  142.232175]  [<ffffffff811a5059>] do_vfs_ioctl+0x99/0x570
[  142.232175]  [<ffffffff8115e488>] ? do_munmap+0x328/0x410
[  142.232175]  [<ffffffff811a55c1>] sys_ioctl+0x91/0xb0
[  142.232175]  [<ffffffff816cc5dd>] system_call_fastpath+0x1a/0x1f
[  142.232175] Code: 00 c1 e8 04 83 f8 02 74 29 85 c0 74 c9 5b 41 5c 5d c3 0f 1f 40 00 31 c9 31 d2 be 34 2f 00 00 48 8b 9f 90 03 00 00 e8 5b f1 fe ff <8b> 03 e9 42 ff ff ff 48 c7 c7 10 b3 24 a0 31 c0 e8 a0 5c 4c e1 
[  142.232175] RIP  [<ffffffffa01f1ba5>] r600_pcie_gart_tlb_flush+0xf5/0x110 [radeon]
[  142.232175]  RSP <ffff88013752bc28>
[  142.232175] CR2: 0000000000000000
[  142.294959] ---[ end trace aabd94dad6d98857 ]---
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