Documentation for dvb-usb-framework module and its devicesIdea behind the dvb-usb-framework=================================In March 2005 I got the new Twinhan USB2.0 DVB-T device. They provided specs and a firmware.Quite keen I wanted to put the driver (with some quirks of course) into dibusb.After reading some specs and doing some USB snooping, it realized, that thedibusb-driver would be a complete mess afterwards. So I decided to do it in adifferent way: With the help of a dvb-usb-framework.The framework provides generic functions (mostly kernel API calls), such as:- Transport Stream URB handling in conjunction with dvb-demux-feed-control  (bulk and isoc are supported)- registering the device for the DVB-API- registering an I2C-adapter if applicable- remote-control/input-device handling- firmware requesting and loading (currently just for the Cypress USB  controllers)- other functions/methods which can be shared by several drivers (such as  functions for bulk-control-commands)- TODO: a I2C-chunker. It creates device-specific chunks of register-accesses  depending on length of a register and the number of values that can be  multi-written and multi-read.The source code of the particular DVB USB devices does just the communicationwith the device via the bus. The connection between the DVB-API-functionalityis done via callbacks, assigned in a static device-description (structdvb_usb_device) each device-driver has to have.For an example have a look in drivers/media/dvb/dvb-usb/vp7045*.Objective is to migrate all the usb-devices (dibusb, cinergyT2, maybe thettusb; flexcop-usb already benefits from the generic flexcop-device) to usethe dvb-usb-lib.TODO: dynamic enabling and disabling of the pid-filter in regard to number offeeds requested.Supported devices========================See the LinuxTV DVB Wiki at www.linuxtv.org for a complete list ofcards/drivers/firmwares:http://www.linuxtv.org/wiki/index.php/DVB_USB0. History & News:  2005-06-30 - added support for WideView WT-220U (Thanks to Steve Chang)  2005-05-30 - added basic isochronous support to the dvb-usb-framework	       added support for Conexant Hybrid reference design and Nebula DigiTV USB  2005-04-17 - all dibusb devices ported to make use of the dvb-usb-framework  2005-04-02 - re-enabled and improved remote control code.  2005-03-31 - ported the Yakumo/Hama/Typhoon DVB-T USB2.0 device to dvb-usb.  2005-03-30 - first commit of the dvb-usb-module based on the dibusb-source. First device is a new driver for the	       TwinhanDTV Alpha / MagicBox II USB2.0-only DVB-T device.  (change from dvb-dibusb to dvb-usb)  2005-03-28 - added support for the AVerMedia AverTV DVB-T USB2.0 device (Thanks to Glen Harris and Jiun-Kuei Jung, AVerMedia)  2005-03-14 - added support for the Typhoon/Yakumo/HAMA DVB-T mobile USB2.0  2005-02-11 - added support for the KWorld/ADSTech Instant DVB-T USB2.0. Thanks a lot to Joachim von Caron  2005-02-02 - added support for the Hauppauge Win-TV Nova-T USB2  2005-01-31 - distorted streaming is gone for USB1.1 devices  2005-01-13 - moved the mirrored pid_filter_table back to dvb-dibusb	     - first almost working version for HanfTek UMT-010	     - found out, that Yakumo/HAMA/Typhoon are predecessors of the HanfTek UMT-010  2005-01-10 - refactoring completed, now everything is very delightful	     - tuner quirks for some weird devices (Artec T1 AN2235 device has sometimes a	       Panasonic Tuner assembled). Tunerprobing implemented. Thanks a lot to Gunnar Wittich.  2004-12-29 - after several days of struggling around bug of no returning URBs fixed.  2004-12-26 - refactored the dibusb-driver, splitted into separate files	     - i2c-probing enabled  2004-12-06 - possibility for demod i2c-address probing	     - new usb IDs (Compro, Artec)  2004-11-23 - merged changes from DiB3000MC_ver2.1	     - revised the debugging	     - possibility to deliver the complete TS for USB2.0  2004-11-21 - first working version of the dib3000mc/p frontend driver.  2004-11-12 - added additional remote control keys. Thanks to Uwe Hanke.  2004-11-07 - added remote control support. Thanks to David Matthews.  2004-11-05 - added support for a new devices (Grandtec/Avermedia/Artec)	     - merged my changes (for dib3000mb/dibusb) to the FE_REFACTORING, because it became HEAD	     - moved transfer control (pid filter, fifo control) from usb driver to frontend, it seems	       better settled there (added xfer_ops-struct)	     - created a common files for frontends (mc/p/mb)  2004-09-28 - added support for a new device (Unkown, vendor ID is Hyper-Paltek)  2004-09-20 - added support for a new device (Compro DVB-U2000), thanks	       to Amaury Demol for reporting	     - changed usb TS transfer method (several urbs, stopping transfer	       before setting a new pid)  2004-09-13 - added support for a new device (Artec T1 USB TVBOX), thanks	       to Christian Motschke for reporting  2004-09-05 - released the dibusb device and dib3000mb-frontend driver  (old news for vp7041.c)  2004-07-15 - found out, by accident, that the device has a TUA6010XS for	       PLL  2004-07-12 - figured out, that the driver should also work with the	       CTS Portable (Chinese Television System)  2004-07-08 - firmware-extraction-2.422-problem solved, driver is now working	       properly with firmware extracted from 2.422	     - #if for 2.6.4 (dvb), compile issue	     - changed firmware handling, see vp7041.txt sec 1.1  2004-07-02 - some tuner modifications, v0.1, cleanups, first public  2004-06-28 - now using the dvb_dmx_swfilter_packets, everything	       runs fine now  2004-06-27 - able to watch and switching channels (pre-alpha)	     - no section filtering yet  2004-06-06 - first TS received, but kernel oops :/  2004-05-14 - firmware loader is working  2004-05-11 - start writing the driver1. How to use?1.1. FirmwareMost of the USB drivers need to download a firmware to the device before startworking.Have a look at the Wikipage for the DVB-USB-drivers to find out, which firmwareyou need for your device:http://www.linuxtv.org/wiki/index.php/DVB_USB1.2. CompilingSince the driver is in the linux kernel, activating the driver inyour favorite config-environment should sufficient. I recommendto compile the driver as module. Hotplug does the rest.If you use dvb-kernel enter the build-2.6 directory run 'make' and 'insmod.shload' afterwards.1.3. Loading the driversHotplug is able to load the driver, when it is needed (because you pluggedin the device).If you want to enable debug output, you have to load the driver manually andfrom withing the dvb-kernel cvs repository.first have a look, which debug level are available:modinfo dvb-usbmodinfo dvb-usb-vp7045etc.modprobe dvb-usb debug=<level>modprobe dvb-usb-vp7045 debug=<level>etc.should do the trick.When the driver is loaded successfully, the firmware file was inthe right place and the device is connected, the "Power"-LED should beturned on.At this point you should be able to start a dvb-capable application. I'm use(t|s)zap, mplayer and dvbscan to test the basics. VDR-xine provides thelong-term test scenario.2. Known problems and bugs- Don't remove the USB device while running an DVB application, your system  will go crazy or die most likely.2.1. Adding support for devicesTODO2.2. USB1.1 Bandwidth limitationA lot of the currently supported devices are USB1.1 and thus they have amaximum bandwidth of about 5-6 MBit/s when connected to a USB2.0 hub.This is not enough for receiving the complete transport stream of aDVB-T channel (which is about 16 MBit/s). Normally this is not aproblem, if you only want to watch TV (this does not apply for HDTV),but watching a channel while recording another channel on the samefrequency simply does not work very well. This applies to all USB1.1DVB-T devices, not just the dvb-usb-devices)The bug, where the TS is distorted by a heavy usage of the device is gonedefinitely. All dvb-usb-devices I was using (Twinhan, Kworld, DiBcom) areworking like charm now with VDR. Sometimes I even was able to record a channeland watch another one.2.3. CommentsPatches, comments and suggestions are very very welcome.3. Acknowledgements   Amaury Demol (ademol@dibcom.fr) and Francois Kanounnikoff from DiBcom for    providing specs, code and help, on which the dvb-dibusb, dib3000mb and    dib3000mc are based.   David Matthews for identifying a new device type (Artec T1 with AN2235)    and for extending dibusb with remote control event handling. Thank you.   Alex Woods for frequently answering question about usb and dvb    stuff, a big thank you.   Bernd Wagner for helping with huge bug reports and discussions.   Gunnar Wittich and Joachim von Caron for their trust for providing    root-shells on their machines to implement support for new devices.   Allan Third and Michael Hutchinson for their help to write the Nebula    digitv-driver.   Glen Harris for bringing up, that there is a new dibusb-device and Jiun-Kuei    Jung from AVerMedia who kindly provided a special firmware to get the device    up and running in Linux.   Jennifer Chen, Jeff and Jack from Twinhan for kindly supporting by	writing the vp7045-driver.   Steve Chang from WideView for providing information for new devices and	firmware files.   Michael Paxton for submitting remote control keymaps.   Some guys on the linux-dvb mailing list for encouraging me.   Peter Schildmann >peter.schildmann-nospam-at-web.de< for his    user-level firmware loader, which saves a lot of time    (when writing the vp7041 driver)   Ulf Hermenau for helping me out with traditional chinese.   André Smoktun and Christian Fr?mmel for supporting me with    hardware and listening to my problems very patiently.