black horizontal bar covering 25% of screen as soon as gnome display manager starts up

Upgraded from Feisty to Gutsy Herd 5 on 20/09/07, when I restarted into gutsy all appeared well until the gnome display manager started. Then a black horizontal bar starting at 25% from the top of the screen to the middle of the screen appeared. I installed all updates and rebooted, but still there. Tried to take a screenshot, but it doesn't show up on that:-(

I am using an Ipex H767 crt monitor (shown as a Compal H767 in the screen and graphics dialog) with an Intel i810 integrated graphics chip, which also seems to be set up properly.

dmesg is as follows:

dov@fred:~$ dmesg
[ 0.000000] Linux version 2.6.22-11-generic (buildd@palmer) (gcc version 4.1.3 20070831 (prerelease) (Ubuntu 4.1.2-16ubuntu1)) #1 SMP Mon Sep 17 03:45:58 GMT 2007 (Ubuntu 2.6.22-11.33-generic)
[ 0.000000] BIOS-provided physical RAM map:
[ 0.000000] BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
[ 0.000000] BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
[ 0.000000] BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved)
[ 0.000000] BIOS-e820: 0000000000100000 - 000000000fee2ec0 (usable)
[ 0.000000] BIOS-e820: 000000000fee2ec0 - 000000000fee6ec0 (ACPI data)
[ 0.000000] BIOS-e820: 000000000fee6ec0 - 000000000feeef00 (ACPI NVS)
[ 0.000000] BIOS-e820: 000000000feeef00 - 0000000010000000 (reserved)
[ 0.000000] BIOS-e820: 00000000fec00000 - 00000000fec01000 (reserved)
[ 0.000000] BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
[ 0.000000] BIOS-e820: 00000000fffc0000 - 0000000100000000 (reserved)
[ 0.000000] 0MB HIGHMEM available.
[ 0.000000] 254MB LOWMEM available.
[ 0.000000] Entering add_active_range(0, 0, 65250) 0 entries of 256 used
[ 0.000000] Zone PFN ranges:
[ 0.000000] DMA 0 -> 4096
[ 0.000000] Normal 4096 -> 65250
[ 0.000000] HighMem 65250 -> 65250
[ 0.000000] early_node_map[1] active PFN ranges
[ 0.000000] 0: 0 -> 65250
[ 0.000000] On node 0 totalpages: 65250
[ 0.000000] DMA zone: 32 pages used for memmap
[ 0.000000] DMA zone: 0 pages reserved
[ 0.000000] DMA zone: 4064 pages, LIFO batch:0
[ 0.000000] Normal zone: 477 pages used for memmap
[ 0.000000] Normal zone: 60677 pages, LIFO batch:15
[ 0.000000] HighMem zone: 0 pages used for memmap
[ 0.000000] DMI 2.2 present.
[ 0.000000] ACPI: RSDP 000FDFE0, 0014 (r0 IBM )
[ 0.000000] ACPI: RSDT 0FEE6E40, 0028 (r1 IBM CDTPWSPT 1010 IBM 0)
[ 0.000000] ACPI: FACP 0FEE6DC0, 0074 (r1 IBM CDTPWSPT 1010 IBM 0)
[ 0.000000] ACPI: DSDT 0FEE3D80, 2BF2 (r1 IBM CDTPWSPT 1000 MSFT 1000007)
[ 0.000000] ACPI: FACS 0FEEEE80, 0040
[ 0.000000] ACPI: PM-Timer IO Port: 0xf808
[ 0.000000] Allocating PCI resources starting at 20000000 (gap: 10000000:eec00000)
[ 0.000000] Built 1 zonelists. Total pages: 64741
[ 0.000000] Kernel command line: root=UUID=10bab7a0-e669-4e08-891d-21cf91648d21 ro quiet splash
[ 0.000000] Found and enabled local APIC!
[ 0.000000] mapped APIC to ffffd000 (fee00000)
[ 0.000000] Enabling fast FPU save and restore... done.
[ 0.000000] Enabling unmasked SIMD FPU exception support... done.
[ 0.000000] Initializing CPU#0
[ 0.000000] PID hash table entries: 1024 (order: 10, 4096 bytes)
[ 0.000000] Detected 601.367 MHz processor.
[ 17.418197] Console: colour VGA+ 80x25
[ 17.418864] Dentry cache hash table entries: 32768 (order: 5, 131072 bytes)
[ 17.419676] Inode-cache hash table entries: 16384 (order: 4, 65536 bytes)
[ 17.457954] Memory: 247308k/261000k available (2017k kernel code, 13204k reserved, 918k data, 364k init, 0k highmem)
[ 17.457992] virtual kernel memory layout:
[ 17.457996] fixmap : 0xfff4d000 - 0xfffff000 ( 712 kB)
[ 17.458001] pkmap : 0xff800000 - 0xffc00000 (4096 kB)
[ 17.458006] vmalloc : 0xd0800000 - 0xff7fe000 ( 751 MB)
[ 17.458011] lowmem : 0xc0000000 - 0xcfee2000 ( 254 MB)
[ 17.458016] .init : 0xc03e3000 - 0xc043e000 ( 364 kB)
[ 17.458021] .data : 0xc02f8436 - 0xc03ddea4 ( 918 kB)
[ 17.458026] .text : 0xc0100000 - 0xc02f8436 (2017 kB)
[ 17.458037] Checking if this processor honours the WP bit even in supervisor mode... Ok.
[ 17.458180] SLUB: Genslabs=22, HWalign=32, Order=0-1, MinObjects=4, CPUs=1, Nodes=1
[ 17.538192] Calibrating delay using timer specific routine.. 1204.08 BogoMIPS (lpj=2408172)
[ 17.538290] Security Framework v1.0.0 initialized
[ 17.538319] SELinux: Disabled at boot.
[ 17.538374] Mount-cache hash table entries: 512
[ 17.538841] CPU: After generic identify, caps: 0383fbff 00000000 00000000 00000000 00000000 00000000 00000000
[ 17.538880] CPU: L1 I cache: 16K, L1 D cache: 16K
[ 17.538890] CPU: L2 cache: 128K
[ 17.538901] CPU: After all inits, caps: 0383fbff 00000000 00000000 00000040 00000000 00000000 00000000
[ 17.538941] Compat vDSO mapped to ffffe000.
[ 17.538993] Checking 'hlt' instruction... OK.
[ 17.554519] SMP alternatives: switching to UP code
[ 17.555147] Freeing SMP alternatives: 11k freed
[ 17.556225] Early unpacking initramfs... done
[ 18.747010] ACPI: Core revision 20070126
[ 18.747331] ACPI: Looking for DSDT in initramfs... error, file /DSDT.aml not found.
[ 18.750679] ACPI: setting ELCR to 0200 (from 0a20)
[ 18.754433] CPU0: Intel Celeron (Coppermine) stepping 03
[ 18.754455] SMP motherboard not detected.
[ 18.861840] Brought up 1 CPUs
[ 18.862342] Booting paravirtualized kernel on bare hardware
[ 18.862565] Time: 20:21:10 Date: 08/20/107
[ 18.862684] NET: Registered protocol family 16
[ 18.863185] EISA bus registered
[ 18.863225] ACPI: bus type pci registered
[ 18.865129] PCI: PCI BIOS revision 2.10 entry at 0xfd80c, last bus=1
[ 18.865140] PCI: Using configuration type 1
[ 18.865147] Setting up standard PCI resources
[ 18.870048] ACPI: EC: Look up EC in DSDT
[ 18.877350] ACPI: Interpreter enabled
[ 18.877368] ACPI: (supports S0 S1 S4 S5)
[ 18.877425] ACPI: Using PIC for interrupt routing
[ 18.894863] ACPI: PCI Root Bridge [PCI0] (0000:00)
[ 18.894894] PCI: Probing PCI hardware (bus 00)
[ 18.895447] PCI quirk: region f800-f87f claimed by ICH4 ACPI/GPIO/TCO
[ 18.895464] PCI quirk: region fc00-fc3f claimed by ICH4 GPIO
[ 18.896103] PCI: Transparent bridge - 0000:00:1e.0
[ 18.896181] ACPI: PCI Interrupt Routing Table [\_SB_.PCI0._PRT]
[ 18.896672] ACPI: PCI Interrupt Routing Table [\_SB_.PCI0.PCI2._PRT]
[ 18.908737] ACPI: PCI Interrupt Link [PIN1] (IRQs 3 4 5 6 7 9 10 *11 12 14 15)
[ 18.909168] ACPI: PCI Interrupt Link [PIN2] (IRQs 3 4 *5 6 7 9 10 11 12 14 15)
[ 18.909555] ACPI: PCI Interrupt Link [PIN3] (IRQs 3 4 5 6 7 9 10 11 12 14 15) *0, disabled.
[ 18.910099] ACPI: PCI Interrupt Link [PIN4] (IRQs 3 4 5 6 7 *9 10 11 12 14 15)
[ 18.910636] Linux Plug and Play Support v0.97 (c) Adam Belay
[ 18.910690] pnp: PnP ACPI init
[ 18.910740] ACPI: bus type pnp registered
[ 18.923068] pnp: PnP ACPI: found 17 devices
[ 18.923085] ACPI: ACPI bus type pnp unregistered
[ 18.923098] PnPBIOS: Disabled by ACPI PNP
[ 18.923363] PCI: Using ACPI for IRQ routing
[ 18.923376] PCI: If a device doesn't work, try "pci=routeirq". If it helps, post a report
[ 18.932795] NET: Registered protocol family 8
[ 18.932805] NET: Registered protocol family 20
[ 18.933218] pnp: 00:0d: ioport range 0x4d0-0x4d1 has been reserved
[ 18.933232] pnp: 00:0d: ioport range 0x800-0x87f has been reserved
[ 18.933243] pnp: 00:0d: ioport range 0xf800-0xf87f has been reserved
[ 18.933254] pnp: 00:0d: ioport range 0x201-0x207 has been reserved
[ 18.933264] pnp: 00:0d: ioport range 0xfc00-0xfc3f has been reserved
[ 18.933279] pnp: 00:0d: iomem range 0xfff80000-0xffffffff could not be reserved
[ 18.933307] pnp: 00:0f: iomem range 0x0-0x9ffff could not be reserved
[ 18.933317] pnp: 00:0f: iomem range 0x100000-0xffffff could not be reserved
[ 18.933328] pnp: 00:0f: iomem range 0x1000000-0xfffffff could not be reserved
[ 18.933349] pnp: 00:10: iomem range 0xc8000-0xcffff has been reserved
[ 18.933360] pnp: 00:10: iomem range 0xe0000-0xe0fff has been reserved
[ 18.933370] pnp: 00:10: iomem range 0xe1000-0xe1fff has been reserved
[ 18.933381] pnp: 00:10: iomem range 0xe2000-0xe2fff has been reserved
[ 18.933662] Time: tsc clocksource has been installed.
[ 18.965154] PCI: Bridge: 0000:00:1e.0
[ 18.965169] IO window: 7000-7fff
[ 18.965184] MEM window: feb00000-febfffff
[ 18.965194] PREFETCH window: disabled.
[ 18.965223] PCI: Setting latency timer of device 0000:00:1e.0 to 64
[ 18.965274] NET: Registered protocol family 2
[ 19.001836] IP route cache hash table entries: 2048 (order: 1, 8192 bytes)
[ 19.002044] TCP established hash table entries: 8192 (order: 4, 98304 bytes)
[ 19.002533] TCP bind hash table entries: 8192 (order: 4, 65536 bytes)
[ 19.002996] TCP: Hash tables configured (established 8192 bind 8192)
[ 19.003009] TCP reno registered
[ 19.014234] checking if image is initramfs...<6>Switched to high resolution mode on CPU 0
[ 19.957792] it is
[ 21.205046] Freeing initrd memory: 7079k freed
[ 21.206731] audit: initializing netlink socket (disabled)
[ 21.206789] audit(1190319671.372:1): initialized
[ 21.218121] VFS: Disk quotas dquot_6.5.1
[ 21.218519] Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
[ 21.219082] io scheduler noop registered
[ 21.219097] io scheduler anticipatory registered
[ 21.219105] io scheduler deadline registered
[ 21.219229] io scheduler cfq registered (default)
[ 21.219280] Boot video device is 0000:00:01.0
[ 21.220290] isapnp: Scanning for PnP cards...
[ 21.573613] isapnp: No Plug & Play device found
[ 21.806344] Real Time Clock Driver v1.12ac
[ 21.806767] Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing enabled
[ 21.806974] serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
[ 21.811264] 00:05: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
[ 21.815587] RAMDISK driver initialized: 16 RAM disks of 65536K size 1024 blocksize
[ 21.816419] input: Macintosh mouse button emulation as /class/input/input0
[ 21.816864] PNP: PS/2 Controller [PNP0303:PS2K,PNP0f13:PS2M] at 0x60,0x64 irq 1,12
[ 21.819222] serio: i8042 KBD port at 0x60,0x64 irq 1
[ 21.819245] serio: i8042 AUX port at 0x60,0x64 irq 12
[ 21.820255] mice: PS/2 mouse device common for all mice
[ 21.820880] EISA: Probing bus 0 at eisa.0
[ 21.820935] Cannot allocate resource for EISA slot 7
[ 21.820947] EISA: Detected 0 cards.
[ 21.821315] TCP cubic registered
[ 21.821376] NET: Registered protocol family 1
[ 21.821699] Testing NMI watchdog ... OK.
[ 21.901150] Using IPI No-Shortcut mode
[ 21.901772] Magic number: 7:466:397
[ 21.902085] hash matches device random
[ 21.904442] Freeing unused kernel memory: 364k freed
[ 21.976301] input: AT Translated Set 2 keyboard as /class/input/input1
[ 23.906239] AppArmor: AppArmor initialized<5>audit(1190319673.872:2): info="AppArmor initialized" pid=1166
[ 23.947673] fuse init (API version 7.8)
[ 23.977741] Failure registering capabilities with primary security module.
[ 24.041317] ACPI: Processor [CPU0] (supports 8 throttling states)
[ 26.907284] SCSI subsystem initialized
[ 26.941773] libata version 2.21 loaded.
[ 26.962073] ata_piix 0000:00:1f.1: version 2.11
[ 26.962281] PCI: Setting latency timer of device 0000:00:1f.1 to 64
[ 26.962835] scsi0 : ata_piix
[ 26.963065] scsi1 : ata_piix
[ 26.963177] ata1: PATA max UDMA/66 cmd 0x000101f0 ctl 0x000103f6 bmdma 0x0001fff0 irq 14
[ 26.963191] ata2: PATA max UDMA/66 cmd 0x00010170 ctl 0x00010376 bmdma 0x0001fff8 irq 15
[ 27.112020] usbcore: registered new interface driver usbfs
[ 27.112119] usbcore: registered new interface driver hub
[ 27.112255] usbcore: registered new device driver usb
[ 27.118196] USB Universal Host Controller Interface driver v3.0
[ 27.127294] ata1.00: ATA-7: Maxtor 6L080P0, BAJ41G20, max UDMA/133
[ 27.127314] ata1.00: 160086528 sectors, multi 16: LBA
[ 27.127344] ata1.00: limited to UDMA/33 due to 40-wire cable
[ 27.143213] ata1.00: configured for UDMA/33
[ 27.237952] 8139too Fast Ethernet driver 0.9.28
[ 27.497538] ata2.00: ATAPI: COMPAQ DVD-ROM GD-2500, 0011, max MWDMA2
[ 27.603278] Floppy drive(s): fd0 is 1.44M
[ 27.701482] ata2.00: configured for MWDMA2
[ 27.709255] scsi 0:0:0:0: Direct-Access ATA Maxtor 6L080P0 BAJ4 PQ: 0 ANSI: 5
[ 27.728585] scsi 1:0:0:0: CD-ROM COMPAQ DVD-ROM GD-2500 0011 PQ: 0 ANSI: 5
[ 27.730073] ACPI: PCI Interrupt Link [PIN4] enabled at IRQ 9
[ 27.730094] PCI: setting IRQ 9 as level-triggered
[ 27.730104] ACPI: PCI Interrupt 0000:00:1f.2[D] -> Link [PIN4] -> GSI 9 (level, low) -> IRQ 9
[ 27.730144] PCI: Setting latency timer of device 0000:00:1f.2 to 64
[ 27.730156] uhci_hcd 0000:00:1f.2: UHCI Host Controller
[ 27.730748] uhci_hcd 0000:00:1f.2: new USB bus registered, assigned bus number 1
[ 27.730816] uhci_hcd 0000:00:1f.2: irq 9, io base 0x0000ff00
[ 27.731363] usb usb1: configuration #1 chosen from 1 choice
[ 27.731480] hub 1-0:1.0: USB hub found
[ 27.731519] hub 1-0:1.0: 2 ports detected
[ 27.835341] ACPI: PCI Interrupt Link [PIN2] enabled at IRQ 5
[ 27.835364] PCI: setting IRQ 5 as level-triggered
[ 27.835375] ACPI: PCI Interrupt 0000:01:04.0[A] -> Link [PIN2] -> GSI 5 (level, low) -> IRQ 5
[ 27.836058] eth0: RealTek RTL8139 at 0xd0814f00, 00:04:e2:11:72:f7, IRQ 5
[ 27.836069] eth0: Identified 8139 chip type 'RTL-8139C'
[ 27.859586] FDC 0 is a post-1991 82077
[ 28.073026] usb 1-2: new full speed USB device using uhci_hcd and address 2
[ 28.101036] sd 0:0:0:0: [sda] 160086528 512-byte hardware sectors (81964 MB)
[ 28.104737] sd 0:0:0:0: [sda] Write Protect is off
[ 28.104761] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
[ 28.104951] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[ 28.105220] sd 0:0:0:0: [sda] 160086528 512-byte hardware sectors (81964 MB)
[ 28.105259] sd 0:0:0:0: [sda] Write Protect is off
[ 28.105269] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
[ 28.105325] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[ 28.105352] sda: sda1 sda2 sda3 sda4
[ 28.195762] sd 0:0:0:0: [sda] Attached SCSI disk
[ 28.250084] usb 1-2: configuration #1 chosen from 1 choice
[ 28.302733] sr0: scsi3-mmc drive: 10x/24x cd/rw xa/form2 cdda tray
[ 28.302756] Uniform CD-ROM driver Revision: 3.20
[ 28.303810] sr 1:0:0:0: Attached scsi CD-ROM sr0
[ 28.323629] sd 0:0:0:0: Attached scsi generic sg0 type 0
[ 28.323730] sr 1:0:0:0: Attached scsi generic sg1 type 5
[ 28.967083] kjournald starting. Commit interval 5 seconds
[ 28.967145] EXT3-fs: mounted filesystem with ordered data mode.
[ 46.541880] i810_smbus 0000:00:01.0: i810/i815 i2c device found.
[ 46.554064] pci_hotplug: PCI Hot Plug PCI Core version: 0.5
[ 46.573284] shpchp: Standard Hot Plug PCI Controller Driver version: 0.4
[ 47.324896] Linux agpgart interface v0.102 (c) Dave Jones
[ 47.355115] agpgart: Detected an Intel i810 Chipset.
[ 47.422389] agpgart: AGP aperture is 64M @ 0xf8000000
[ 47.764460] iTCO_vendor_support: vendor-support=0
[ 47.981168] iTCO_wdt: Intel TCO WatchDog Timer Driver v1.01 (21-Jan-2007)
[ 47.981473] iTCO_wdt: failed to reset NO_REBOOT flag, reboot disabled by hardware
[ 47.981497] iTCO_wdt: No card detected
[ 48.039688] intel_rng: Firmware space is locked read-only. <4>intel_rng: If you can't or
[ 48.039698] don't want to <4>intel_rng: disable this in firmware setup, and <4>intel_rng: if
[ 48.039705] you are certain that your <4>intel_rng: system has a functional
[ 48.039711] RNG, try<4>intel_rng: using the 'no_fwh_detect' option.
[ 50.416768] /build/buildd/linux-source-2.6.22-2.6.22/drivers/usb/class/usblp.c: usblp0: USB Bidirectional printer dev 2 if 0 alt 0 proto 2 vid 0x04A9 pid 0x1065
[ 50.416869] usbcore: registered new interface driver usblp
[ 50.416884] /build/buildd/linux-source-2.6.22-2.6.22/drivers/usb/class/usblp.c: v0.13: USB Printer Device Class driver
[ 50.879371] input: ImExPS/2 Logitech Wheel Mouse as /class/input/input2
[ 50.883023] parport_pc 00:02: reported by Plug and Play ACPI
[ 50.883153] parport0: PC-style at 0x378 (0x778), irq 7, dma 3 [PCSPP,TRISTATE,COMPAT,EPP,ECP,DMA]
[ 50.897526] input: PC Speaker as /class/input/input3
[ 51.781334] ACPI: PCI Interrupt 0000:00:1f.5[B] -> Link [PIN2] -> GSI 5 (level, low) -> IRQ 5
[ 51.781405] PCI: Setting latency timer of device 0000:00:1f.5 to 64
[ 52.452245] intel8x0_measure_ac97_clock: measured 54172 usecs
[ 52.452262] intel8x0: clocking to 48000
[ 53.826533] lp0: using parport0 (interrupt-driven).
[ 54.061967] Adding 2097276k swap on /dev/sda3. Priority:-1 extents:1 across:2097276k
[ 54.537502] EXT3 FS on sda2, internal journal
[ 71.114906] kjournald starting. Commit interval 5 seconds
[ 71.115536] EXT3 FS on sda4, internal journal
[ 71.115558] EXT3-fs: mounted filesystem with ordered data mode.
[ 74.091060] No dock devices found.
[ 74.252979] input: Power Button (FF) as /class/input/input4
[ 74.254067] ACPI: Power Button (FF) [PWRF]
[ 74.280956] input: Power Button (CM) as /class/input/input5
[ 74.281981] ACPI: Power Button (CM) [PWRB]
[ 80.153752] eth0: link up, 100Mbps, full-duplex, lpa 0x41E1
[ 83.811241] ppdev: user-space parallel port driver
[ 84.714463] audit(1190283735.904:3): operation="inode_permission" requested_mask="a" denied_mask="a" name="/dev/tty" pid=4663 profile="/usr/sbin/cupsd"
[ 84.995670] IBM machine detected. Enabling interrupts during APM calls.
[ 84.995693] apm: BIOS version 1.2 Flags 0x03 (Driver version 1.16ac)
[ 84.995702] apm: overridden by ACPI.
[ 87.434480] Non-volatile memory driver v1.2
[ 87.644436] input: /usr/sbin/thinkpad-keys as /class/input/input6
[ 92.549311] Failure registering capabilities with primary security module.
[ 99.506557] NET: Registered protocol family 17
[ 106.100185] NET: Registered protocol family 10
[ 106.101170] lo: Disabled Privacy Extensions
[ 117.050703] eth0: no IPv6 routers present
dov@fred:~$