[linux-dvb] USB 1.1 support for dvb_usb_dtt200u dvb-t stick

M A Young m.a.young at durham.ac.uk
Wed Mar 28 21:27:14 CEST 2007


I have a Freecom dvb-t USB stick (14aa:022b with
dvb-usb-wt220u-zl0353-01.fw firmware) which works fine when connected via
my USB 2.0 CardBus card, but not the onboard USB 1.1 port, where the card
initializes but fails to start when attempting to watch TV and this is a
problem if the CardBus slot is occupied with something else.

I have been doing some investigating and it seems that the differences are
that under USB 2.0 the usb settings are

T:  Bus=05 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  3 Spd=480 MxCh= 0
D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=14aa ProdID=022b Rev= 5.21
S:  Manufacturer=Digital TV Receiver
S:  Product=Digital TV Receiver
C:* #Ifs= 1 Cfg#= 1 Atr=a0 MxPwr=450mA
I:  If#= 0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00
Driver=dvb_usb_dtt200u
E:  Ad=01(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=82(I) Atr=02(Bulk) MxPS= 189 Ivl=0ms

but under USB 1.1 they are

T:  Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  3 Spd=12  MxCh= 0
D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=14aa ProdID=022b Rev= 5.21
S:  Manufacturer=Digital TV Receiver
S:  Product=Digital TV Receiver
C:* #Ifs= 1 Cfg#= 1 Atr=a0 MxPwr=450mA
I:  If#= 0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00
Driver=dvb_usb_dtt200u
E:  Ad=01(O) Atr=02(Bulk) MxPS=  64 Ivl=0ms
E:  Ad=81(I) Atr=02(Bulk) MxPS=  64 Ivl=0ms
E:  Ad=82(I) Atr=01(Isoc) MxPS= 940 Ivl=1ms

so the main data stream has gone from Bulk under 2.0 to Isoc under 1.1. If
I naively change the stream settings in wt220u_zl0353_properties from a
USB_BULK one to USB_ISOC settings (from another driver) then the card
works under USB 1.1 instead.

Is it possible that this driver could auto-detect the USB speed and use
the appropriate USB transfer mode so that it works under both USB 1.1 and
USB 2.0?

	Michael Young



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