Fedora Core 4, with the included Bluez;
kernel-2.6.14-1.1656_FC4, bluez-utils-2.15-7.
(This software itself appears to have minor issues, like "dund" not enabled by default. If you won't "dial-up" to or from your computer you won't notice. FC4 is kind-of old anyway.)

There may be different hardware with same model name. This one says "P/N 18-1AGBD22", where notes
on the CNet (Windows) driver pages at
http://www.cnet.com.tw/download/cbd-220.htm
hint that the "A" signifies this hardware. Apparently based on CSR.
From cat /proc/bus/usb/devices:

T: Bus=02 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 3 Spd=12 MxCh= 0
D: Ver= 2.00 Cls=e0(unk. ) Sub=01 Prot=01 MxPS=64 #Cfgs= 1
P: Vendor=0a12 ProdID=0001 Rev=19.58
C:* #Ifs= 2 Cfg#= 1 Atr=c0 MxPwr= 0mA
I: If#= 0 Alt= 0 #EPs= 3 Cls=e0(unk. ) Sub=01 Prot=01 Driver=hci_usb
E: Ad=81(I) Atr=03(Int.) MxPS= 16 Ivl=1ms
E: Ad=02(O) Atr=02(Bulk) MxPS= 64 Ivl=0ms
E: Ad=82(I) Atr=02(Bulk) MxPS= 64 Ivl=0ms
I: If#= 1 Alt= 0 #EPs= 2 Cls=e0(unk. ) Sub=01 Prot=01 Driver=hci_usb
E: Ad=03(O) Atr=01(Isoc) MxPS= 0 Ivl=1ms
E: Ad=83(I) Atr=01(Isoc) MxPS= 0 Ivl=1ms
I: If#= 1 Alt= 1 #EPs= 2 Cls=e0(unk. ) Sub=01 Prot=01 Driver=hci_usb
E: Ad=03(O) Atr=01(Isoc) MxPS= 9 Ivl=1ms
E: Ad=83(I) Atr=01(Isoc) MxPS= 9 Ivl=1ms
I: If#= 1 Alt= 2 #EPs= 2 Cls=e0(unk. ) Sub=01 Prot=01 Driver=hci_usb
E: Ad=03(O) Atr=01(Isoc) MxPS= 17 Ivl=1ms
E: Ad=83(I) Atr=01(Isoc) MxPS= 17 Ivl=1ms
I: If#= 1 Alt= 3 #EPs= 2 Cls=e0(unk. ) Sub=01 Prot=01 Driver=hci_usb
E: Ad=03(O) Atr=01(Isoc) MxPS= 25 Ivl=1ms
E: Ad=83(I) Atr=01(Isoc) MxPS= 25 Ivl=1ms
I: If#= 1 Alt= 4 #EPs= 2 Cls=e0(unk. ) Sub=01 Prot=01 Driver=hci_usb
E: Ad=03(O) Atr=01(Isoc) MxPS= 33 Ivl=1ms
E: Ad=83(I) Atr=01(Isoc) MxPS= 33 Ivl=1ms
I: If#= 1 Alt= 5 #EPs= 2 Cls=e0(unk. ) Sub=01 Prot=01 Driver=hci_usb
E: Ad=03(O) Atr=01(Isoc) MxPS= 49 Ivl=1ms
E: Ad=83(I) Atr=01(Isoc) MxPS= 49 Ivl=1ms