knc1 dvb-c card frequently looses CAM when switching channels quickly

Hello,
I have experienced the following on my vdr machine:

When changing channels quickly between encrypted channels, the card loosses cam and I get the following in my /var/log/messages:

[   67.645354] dvb_ca adapter 0: DVB CAM detected and initialised successfully
[   84.659047] budget-av: cam inserted A
[   85.656855] dvb_ca adapter 0: DVB CAM detected and initialised successfully
[60706.931218] budget-av: cam inserted A
[60707.485891] dvb_ca adapter 0: DVB CAM detected and initialised

successfully

lspci -vvv

03:00.0 Multimedia controller: Philips Semiconductors SAA7146 (rev 01)
Subsystem: KNC One Device 0022
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 64 (3750ns min, 9500ns max)
Interrupt: pin A routed to IRQ 19
Region 0: Memory at f9fffc00 (32-bit, non-prefetchable) [size=512]
Kernel driver in use: budget_av

I am using drivers from kernel 2.6.34.
Any Ideas for solving this issue?
Thx.
Halim