I also have been having a problem with console messages:

cx88_wakeup: 2 buffers handled (should be 1)
cx88_wakeup: 4 buffers handled (should be 1)

every second or so, and at the same time, VERY jerky video with mythfrontend, and 2.6.20-series kernels, Most recently with 2.6.23.1. My tv card is branded DVico Fusion DVB-T Plus. dmesg, and lspci -vv shown below 

So I went BACK to kernel 2.6.19.1, and no more console messages !! But video still VERY jerky with mythfrontend. Unwatchable. The utility "top" shows that mythfrontend is tying up 90-99% of cpu time.  Hence why the jerky video, I suspect.

But Kaffeine runs fine, 15-20% of cpu time, and smooth video playback. Some video artifact in fast-motion scenes, but really quite acceptable.

The system is a P4 with 1GB RAM, asus main board. I have trolled google at length for a solution, but to no avail, so I thought that I would tack on my experiences to this thread as further evidence that there is indeed a bug somewhere. Hopefully someone will find it in due course.

Other factors: I'm in Australia. Some of the threads that I've seen mention that there digital tv transmission here is different somehow.

dmesg says:

CORE cx88[0]: subsystem: 18ac:db10, board: DViCO FusionHDTV DVB-T Plus [card=21,autodetected]
TV tuner 4 at 0x1fe, Radio tuner -1 at 0x1fe
cx88[0]/0: found at 0000:02:0e.0, rev: 5, irq: 10, latency: 32, mmio: 0xdb000000
cx88[0]/0: registered device video0 [v4l2]
cx88[0]/0: registered device vbi0
PCI: Enabling device 0000:02:0e.2 (0014 -> 0016)
ACPI: PCI Interrupt 0000:02:0e.2[A] -> Link [LNKC] -> GSI 10 (level, low) -> IRQ 10
cx88[0]/2: found at 0000:02:0e.2, rev: 5, irq: 10, latency: 32, mmio: 0xda000000
cx88[0]/2: cx2388x based dvb card
DVB: registering new adapter (cx88[0]).
DVB: registering frontend 0 (Zarlink MT352 DVB-T)...
cx2388x blackbird driver version 0.0.6 loaded

lspci -vv says:

00:00.0 Host bridge: Intel Corporation 82845 845 [Brookdale] Chipset Host Bridge (rev 11)
        Subsystem: ASUSTeK Computer Inc. Unknown device 8088
        Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
        Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort+ >SERR- <PERR-
        Latency: 0
        Region 0: Memory at f8000000 (32-bit, prefetchable) [size=64M]
        Capabilities: [e4] Vendor Specific Information
        Capabilities: [a0] AGP version 2.0
                Status: RQ=32 Iso- ArqSz=0 Cal=0 SBA+ ITACoh- GART64- HTrans- 64bit- FW+ AGP3- Rate=x1,x2,x4
                Command: RQ=1 ArqSz=0 Cal=0 SBA- AGP- GART64- 64bit- FW- Rate=<none>

00:01.0 PCI bridge: Intel Corporation 82845 845 [Brookdale] Chipset AGP Bridge (rev 11) (prog-if 00 [Normal decode])
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
        Status: Cap- 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR-
        Latency: 64
        Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
        Memory behind bridge: dd000000-dfdfffff
        Prefetchable memory behind bridge: dff00000-f7ffffff
        Secondary status: 66MHz+ FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort+ <SERR- <PERR-
        BridgeCtl: Parity- SERR- NoISA- VGA+ MAbort- >Reset- FastB2B-

00:1d.0 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #1 (rev 01) (prog-if 00 [UHCI])
        Subsystem: ASUSTeK Computer Inc. P4B533
        Control: I/O+ Mem- BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
        Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
        Latency: 0
        Interrupt: pin A routed to IRQ 11
        Region 4: I/O ports at d800 [size=32]

00:1d.1 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #2 (rev 01) (prog-if 00 [UHCI])
        Subsystem: ASUSTeK Computer Inc. P4B533
        Control: I/O+ Mem- BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
        Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
        Latency: 0
        Interrupt: pin B routed to IRQ 4
        Region 4: I/O ports at d400 [size=32]

00:1d.2 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #3 (rev 01) (prog-if 00 [UHCI])
        Subsystem: ASUSTeK Computer Inc. P4B533
        Control: I/O+ Mem- BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
        Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
        Latency: 0
        Interrupt: pin C routed to IRQ 10
        Region 4: I/O ports at d000 [size=32]

00:1d.7 USB Controller: Intel Corporation 82801DB/DBM (ICH4/ICH4-M) USB2 EHCI Controller (rev 01) (prog-if 20 [EHCI])
        Subsystem: ASUSTeK Computer Inc. P4B533
        Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
        Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
        Latency: 0
        Interrupt: pin D routed to IRQ 11
        Region 0: Memory at dc800000 (32-bit, non-prefetchable) [size=1K]
        Capabilities: [50] Power Management version 2
                Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA PME(D0+,D1-,D2-,D3hot+,D3cold+)
                Status: D0 PME-Enable- DSel=0 DScale=0 PME-
        Capabilities: [58] Debug port

00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 81) (prog-if 00 [Normal decode])
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B-
        Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR+
        Latency: 0
        Bus: primary=00, secondary=02, subordinate=02, sec-latency=32
        I/O behind bridge: 0000b000-0000bfff
        Memory behind bridge: da000000-dc7fffff
        Prefetchable memory behind bridge: dfe00000-dfefffff
        Secondary status: 66MHz- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort+ <SERR- <PERR-
        BridgeCtl: Parity- SERR+ NoISA+ VGA- MAbort- >Reset- FastB2B-

00:1f.0 ISA bridge: Intel Corporation 82801DB/DBL (ICH4/ICH4-L) LPC Interface Bridge (rev 01)
        Control: I/O+ Mem+ BusMaster+ SpecCycle+ MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B-
        Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
        Latency: 0

00:1f.1 IDE interface: Intel Corporation 82801DB (ICH4) IDE Controller (rev 01) (prog-if 8a [Master SecP PriP])
        Subsystem: ASUSTeK Computer Inc. P4B533
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
        Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
        Latency: 0
        Interrupt: pin A routed to IRQ 10
        Region 0: I/O ports at <unassigned>
        Region 1: I/O ports at <unassigned>
        Region 2: I/O ports at <unassigned>
        Region 3: I/O ports at <unassigned>
        Region 4: I/O ports at f000 [size=16]
        Region 5: Memory at 50000000 (32-bit, non-prefetchable) [size=1K]

01:00.0 VGA compatible controller: nVidia Corporation G73 [GeForce 7600 GS] (rev a2) (prog-if 00 [VGA controller])
        Subsystem: ASUSTeK Computer Inc. Unknown device 8235
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
        Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
        Latency: 64 (1250ns min, 250ns max)
        Interrupt: pin A routed to IRQ 11
        Region 0: Memory at de000000 (32-bit, non-prefetchable) [size=16M]
        Region 1: Memory at e0000000 (32-bit, prefetchable) [size=256M]
        Region 2: Memory at dd000000 (32-bit, non-prefetchable) [size=16M]
        Expansion ROM at dffe0000 [disabled] [size=128K]
        Capabilities: [60] Power Management version 2
                Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
                Status: D0 PME-Enable- DSel=0 DScale=0 PME-
        Capabilities: [44] AGP version 3.0
                Status: RQ=32 Iso- ArqSz=0 Cal=0 SBA+ ITACoh- GART64- HTrans- 64bit- FW+ AGP3- Rate=x1,x2,x4
                Command: RQ=1 ArqSz=0 Cal=0 SBA- AGP- GART64- 64bit- FW- Rate=<none>

02:03.0 Multimedia audio controller: C-Media Electronics Inc CM8738 (rev 10)
        Subsystem: ASUSTeK Computer Inc. CMI8738 6ch-MX
        Control: I/O+ Mem- BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping+ SERR- FastB2B-
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
        Latency: 32 (500ns min, 6000ns max)
        Interrupt: pin A routed to IRQ 3
        Region 0: I/O ports at b800 [size=256]
        Capabilities: [c0] Power Management version 2
                Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
                Status: D0 PME-Enable- DSel=0 DScale=0 PME-

02:0d.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 10)
        Subsystem: AOPEN Inc. Unknown device 0027
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
        Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
        Latency: 32 (8000ns min, 16000ns max)
        Interrupt: pin A routed to IRQ 3
        Region 0: I/O ports at b400 [size=256]
        Region 1: Memory at dc000000 (32-bit, non-prefetchable) [size=256]
        [virtual] Expansion ROM at dfe00000 [disabled] [size=16K]
        Capabilities: [50] Power Management version 2
                Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=375mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
                Status: D0 PME-Enable- DSel=0 DScale=0 PME-

02:0e.0 Multimedia video controller: Conexant CX23880/1/2/3 PCI Video and Audio Decoder (rev 05)
        Subsystem: DViCO Corporation Unknown device db10
        Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop- ParErr- Stepping- SERR- FastB2B-
        Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
        Latency: 32 (5000ns min, 13750ns max), Cache Line Size: 32 bytes
        Interrupt: pin A routed to IRQ 10
        Region 0: Memory at db000000 (32-bit, non-prefetchable) [size=16M]
        Capabilities: [44] Vital Product Data
        Capabilities: [4c] Power Management version 2
                Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
                Status: D0 PME-Enable- DSel=0 DScale=0 PME-

02:0e.2 Multimedia controller: Conexant CX23880/1/2/3 PCI Video and Audio Decoder [MPEG Port] (rev 05)
        Subsystem: DViCO Corporation DVICO FusionHDTV DVB-T Plus
        Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop- ParErr- Stepping- SERR- FastB2B-
        Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
        Latency: 32 (1500ns min, 22000ns max), Cache Line Size: 32 bytes
        Interrupt: pin A routed to IRQ 10
        Region 0: Memory at da000000 (32-bit, non-prefetchable) [size=16M]
        Capabilities: [4c] Power Management version 2
                Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
                Status: D0 PME-Enable- DSel=0 DScale=0 PME-