What does the `dmesg` error: "composite sync not supported" mean?

Question

Question: I see [ 20.473125] composite sync not supported and several such entries when I run dmesg. What do they mean?

Background: I'm trying to debug a problem where my laptop won't suspend. Since acpi seems happy and I can suspend easily from the command line, I've turned to tracking down all boot-up errors/warnings.

So I run dmesg | grep not and, amongst other shtuff, I get:

728:[   17.267120] composite sync not supported
733:[   18.009061] composite sync not supported
740:[   18.159289] registered panic notifier
749:[   18.162500] vga16fb: not registering due to another framebuffer present
757:[   18.598251] composite sync not supported
776:[   20.473125] composite sync not supported
777:[   20.932266] composite sync not supported
778:[   28.350231] composite sync not supported
779:[   28.924913] composite sync not supported
780:[   35.480658] composite sync not supported

And the full log for the few lines right around that first appearance (line 728) is listed at the bottom of my post (I'd happily include anything else). Any ideas what could be causing this? I've read several sites:

1. Ubuntuforums #1
2. IRC Chat #1

One post talks about ??Adobe flash?? causing this error?

Some others also suggest that it might be an nvidia related problem, but I've got a Dell Latitude D630 with an integrated Intel graphics -- so nvidia isn't the problem.

[   17.207142] phy0: Selected rate control algorithm 'minstrel'
[   17.207833] Registered led device: b43-phy0::tx
[   17.207849] Registered led device: b43-phy0::rx
[   17.207865] Registered led device: b43-phy0::radio
[   17.207927] Broadcom 43xx driver loaded [ Features: PL, Firmware-ID: FW13 ]
[   17.267120] composite sync not supported
[   17.415795] EXT4-fs (sda2): mounted filesystem with ordered data mode
[   17.602131] [drm] initialized overlay support
[   17.620201] input: DualPoint Stick as /devices/platform/i8042/serio1/input/input7
[   17.641192] input: AlpsPS/2 ALPS DualPoint TouchPad as /devices/platform/i8042/serio1/input/input8
[   18.009061] composite sync not supported
[   18.106042] pcmcia_socket pcmcia_socket0: cs: IO port probe 0x100-0x3af: clean.
[   18.108115] pcmcia_socket pcmcia_socket0: cs: IO port probe 0x3e0-0x4ff: clean.
[   18.108941] pcmcia_socket pcmcia_socket0: cs: IO port probe 0x820-0x8ff: clean.
[   18.109676] pcmcia_socket pcmcia_socket0: cs: IO port probe 0xc00-0xcf7: clean.
[   18.110356] pcmcia_socket pcmcia_socket0: cs: IO port probe 0xa00-0xaff: clean.
[   18.159286] fb0: inteldrmfb frame buffer device
[   18.159289] registered panic notifier
[   18.160218] input: Video Bus as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A03:00/LNXVIDEO:01/input/input9
[   18.160286] ACPI: Video Device [VID1] (multi-head: yes  rom: no  post: no)
[   18.160334] ACPI Warning for \_SB_.PCI0.VID2._DOD: Return Package has no elements (empty) (20090903/nspredef-433)
[   18.160432] input: Video Bus as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A03:00/LNXVIDEO:02/input/input10
[   18.160491] ACPI: Video Device [VID2] (multi-head: yes  rom: no  post: no)
[   18.160539] [drm] Initialized i915 1.6.0 20080730 for 0000:00:02.0 on minor 0
[   18.162494] vga16fb: initializing
[   18.162497] vga16fb: mapped to 0xc00a0000
[   18.162500] vga16fb: not registering due to another framebuffer present
[   18.176091] HDA Intel 0000:00:1b.0: PCI INT A -> GSI 21 (level, low) -> IRQ 21
[   18.176123] HDA Intel 0000:00:1b.0: setting latency timer to 64
[   18.285752] input: HDA Digital PCBeep as /devices/pci0000:00/0000:00:1b.0/input/input11
[   18.312497] input: HDA Intel Mic at Ext Left Jack as /devices/pci0000:00/0000:00:1b.0/sound/card0/input12
[   18.312586] input: HDA Intel HP Out at Ext Left Jack as /devices/pci0000:00/0000:00:1b.0/sound/card0/input13
[   18.328043] usbcore: registered new interface driver ndiswrapper
[   18.460909] Console: switching to colour frame buffer device 180x56
[   18.598251] composite sync not supported

Answer 1

Well, still don't know what it means. However, to get it to go away, I followed the instructions here and added the option nomodeset to grub. Now those errors are gone as well as a few other things which I thought looked odd, like:

vga16fb: not registering due to another framebuffer present

and others. Hope this helps others... I'm not going to award myself the answer. If someone could explain this error, and (?perhaps?) how it's related to Xorg's compositing, then I'll happily award points (or bounties -- if I ever get enough points to do so). ~ m

Please note, that I did at a minimum add the Xorg extension to disable compositing and this only made one of the five lines which read composite sync not supported go away. So I undid this change and kept searching until I found the above grub option which removed all of the errors.