Comment 27 for bug 809956

A similar problem happens on my machine regularly, although it doesn't happen at boot time.

It seems to have something to do with the launcher, when I move the mouse over and icon on the the launcher occasionally the screen goes blank for 30 seconds, then comes back, screen updates, then goes blank away again and repeats for a while. Its not every time I use the launcher just sometimes. Maybe once a day.

If I try early enough I can get to a console and reboot the machine, otherwise it just completely locks up after a while.

I've attached a comment to this bug as it seems very similar, but can create a new one if required.

I have a dual monitor setup, both with the resolution of both monitors set to 1920x1080.

I did try out the kernel 2.6.39 from http://kernel.ubuntu.com/~kernel-ppa/mainline/v2.6.39-rc4-natty/

That seemed to fix this problem, but did hang in other ways although less frequently.

Here is graphics card info

01:00.0 VGA compatible controller: ATI Technologies Inc RV710 [Radeon HD 4350] (prog-if 00 [VGA controller])
        Subsystem: PC Partner Limited Device e112
        Flags: bus master, fast devsel, latency 0, IRQ 43
        Memory at d0000000 (64-bit, prefetchable) [size=256M]
        Memory at feaf0000 (64-bit, non-prefetchable) [size=64K]
        I/O ports at d000 [size=256]
        Expansion ROM at feac0000 [disabled] [size=128K]
        Capabilities: <access denied>
        Kernel driver in use: radeon
        Kernel modules: radeon

Here is some information from kern.log

Sep 19 10:25:11 lse001600 kernel: [259485.360044] ------------[ cut here ]------------
Sep 19 10:25:11 lse001600 kernel: [259485.360064] WARNING: at /build/buildd/linux-2.6.38/drivers/gpu/drm/radeon/radeon_fence.c:248 radeon_fence_wait+0x36f/0x3e0 [radeon]()
Sep 19 10:25:11 lse001600 kernel: [259485.360066] Hardware name: K9A2VM-FD R01
Sep 19 10:25:11 lse001600 kernel: [259485.360068] GPU lockup (waiting for 0x002181CA last fence id 0x002181C8)
Sep 19 10:25:11 lse001600 kernel: [259485.360069] Modules linked in: binfmt_misc xt_limit xt_tcpudp ipt_LOG ipt_MASQUERADE xt_DSCP ipt_REJECT nf_conntrack_irc nf_conntrack_ftp xt_state parport_pc ppdev iptable_nat nf_nat nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 iptable_mangle iptable_filter ip_tables x_tables snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_hwdep snd_pcm snd_seq_midi radeon snd_rawmidi snd_seq_midi_event ttm drm_kms_helper psmouse snd_seq drm snd_timer snd_seq_device lp parport sp5100_tco i2c_piix4 serio_raw i2c_algo_bit snd edac_core soundcore k10temp snd_page_alloc edac_mce_amd usbhid hid pata_atiixp ahci r8169 libahci
Sep 19 10:25:11 lse001600 kernel: [259485.360096] Pid: 991, comm: Xorg Tainted: G W 2.6.38-11-generic #48-Ubuntu
Sep 19 10:25:11 lse001600 kernel: [259485.360097] Call Trace:
Sep 19 10:25:11 lse001600 kernel: [259485.360103] [<ffffffff81065cbf>] ? warn_slowpath_common+0x7f/0xc0
Sep 19 10:25:11 lse001600 kernel: [259485.360105] [<ffffffff81065db6>] ? warn_slowpath_fmt+0x46/0x50
Sep 19 10:25:11 lse001600 kernel: [259485.360116] [<ffffffffa01c47cf>] ? radeon_fence_wait+0x36f/0x3e0 [radeon]
Sep 19 10:25:11 lse001600 kernel: [259485.360119] [<ffffffff81087fb0>] ? autoremove_wake_function+0x0/0x40
Sep 19 10:25:11 lse001600 kernel: [259485.360129] [<ffffffffa01c50b1>] ? radeon_sync_obj_wait+0x11/0x20 [radeon]
Sep 19 10:25:11 lse001600 kernel: [259485.360136] [<ffffffffa0180b0d>] ? ttm_bo_wait+0xfd/0x1b0 [ttm]
Sep 19 10:25:11 lse001600 kernel: [259485.360140] [<ffffffffa0180e88>] ? ttm_bo_list_ref_sub+0x28/0x30 [ttm]
Sep 19 10:25:11 lse001600 kernel: [259485.360152] [<ffffffffa01ddad3>] ? radeon_gem_wait_idle_ioctl+0x93/0x110 [radeon]
Sep 19 10:25:11 lse001600 kernel: [259485.360162] [<ffffffffa00e8384>] ? drm_ioctl+0x3e4/0x4c0 [drm]
Sep 19 10:25:11 lse001600 kernel: [259485.360173] [<ffffffffa01dda40>] ? radeon_gem_wait_idle_ioctl+0x0/0x110 [radeon]
Sep 19 10:25:11 lse001600 kernel: [259485.360176] [<ffffffff8100b7b1>] ? handle_signal+0x131/0x260
Sep 19 10:25:11 lse001600 kernel: [259485.360179] [<ffffffff810156d1>] ? fpu_finit+0x21/0x40
Sep 19 10:25:11 lse001600 kernel: [259485.360181] [<ffffffff810157fa>] ? init_fpu+0x4a/0x150
Sep 19 10:25:11 lse001600 kernel: [259485.360184] [<ffffffff811764ff>] ? do_vfs_ioctl+0x8f/0x360
Sep 19 10:25:11 lse001600 kernel: [259485.360185] [<ffffffff8100bd06>] ? sys_rt_sigreturn+0x106/0x140
Sep 19 10:25:11 lse001600 kernel: [259485.360188] [<ffffffff81176861>] ? sys_ioctl+0x91/0xa0
Sep 19 10:25:11 lse001600 kernel: [259485.360190] [<ffffffff8100c002>] ? system_call_fastpath+0x16/0x1b
Sep 19 10:25:11 lse001600 kernel: [259485.360191] ---[ end trace 31b4c38a1d934b31 ]---

Can get more info if required

Cheers

Rupert