[linux-dvb] Couple of question regarding installation

Klaus Frahm frahm at irsamc.ups-tlse.fr
Sat Oct 14 22:16:47 CEST 2006


 > Am Samstag, 14. Oktober 2006 16:35 schrieb Patrick Boettcher:
 > > Where is the driver from you are using? Can you try the drivers from
 > > latest hg (v4l-dvb)?

 > I'm using only the drivers from the kernel (2.6.17.6) and the
 > firmware. No other drivers? Do I need to v4l userscape stuff?
 >
 > horus linux # grep DVB .config
 > CONFIG_DVB=y
 > CONFIG_DVB_CORE=m
 > CONFIG_DVB_USB=m
 > CONFIG_DVB_USB_A800=m
 > CONFIG_DVB_DIB3000MC=m
 >
 >
 > Thanks,
 >
 > Florian

Dear Florian,

I am using the same DVB-T Tuner AverTV A800 USB 2.0 and it works fine 
but there are some particularities/bugs/patches to take into account:

---------------------
1) Concerning the modules you list I think you are missing some, in my 
case I have:
grep DVB .config | grep -v "#"
=>
CONFIG_DVB=y
CONFIG_DVB_CORE=m
CONFIG_DVB_USB=m
CONFIG_DVB_USB_A800=m
CONFIG_DVB_USB_DIBUSB_MB=m
CONFIG_DVB_USB_DIBUSB_MC=m
CONFIG_DVB_DIB3000MB=m
CONFIG_DVB_DIB3000MC=m
CONFIG_DVB_PLL=m

I think here the support for 3000MB and DiBUSB_MB is not necessary (but 
I still compiled these modules) but you absolutely need 
CONFIG_DVB_USB_DIBUSB_MC=m which is normally well selected when you use 
"make xconfig" to configure your kernel. I believe this is your present 
frontend problem. Furthermore there is also DVB_PLL you will need (I 
suppose).
The modules I have loaded are (output from lsmod):

dvb_usb_a800           23940  0
dvb_usb_dibusb_common    26756  1 dvb_usb_a800
mt2060                 22148  1 dvb_usb_dibusb_common
dib3000mc              29060  0 dvb_usb_dibusb_common
dibx000_common         20996  1 dib3000mc
dvb_usb                39944  2 dvb_usb_a800,dvb_usb_dibusb_common
dvb_core              101040  1 dvb_usb
firmware_class         27904  1 dvb_usb
dvb_pll                32644  1 dvb_usb_dibusb_common,dvb_usb

here the mt2060 is also loaded (from a quite late version of the driver 
and in 2.6.17.x you will not have this one, that is okay).

----------------------
2.) A part from you first order problem to have all modules there are 
other problems which require your attention. In principle the driver for 
the AverTV A800 works well but if you have the new version of this 
tuner, such as me, than there is no need for a firmware the driver 
version in kernel up to 2.6.18 will not properly initialize the module 
(a confusion between cold and warm state). There is a simple patch you 
can apply to solve this problem and which was discussed several months 
ago between Patrick, me, and some other people:
http://www.linuxtv.org/pipermail/linux-dvb/2006-July/011456.html
http://www.linuxtv.org/pipermail/linux-dvb/2006-June/011298.html
the second link contains the patch and you can apply it to 2.6.17.x or 
2.6.18 without any problem.

-----------------------
3.) There is also another bug/problem with the driver, maybe not with 
the a800.c file but with the frontend or something related. After 
getting a first lock there is no video flux until immediately getting a 
second lock. With xine this does not create problem but with vlc you 
have first to clic on stop and then on play to start the video flux. 
There is also a nice work around using tzap. Details about this problem 
and the work around in the second half of this message:
http://www.linuxtv.org/pipermail/linux-dvb/2006-June/011248.html
This problem is present in 2.6.17.x but it is repaired in 2.6.18 !!!

-----------------------
4.) And now the worst: There is NEW bug, corruption of the mpeg flux for 
certain multiplexes !! I have tested this on two very different 
machines. This bug is new and appears in the latest drivers. I will 
report about this bug/problem in a different thread. For the moment 
being I strongly suggest that you DO NOT USE use the very latest 
DVB-driver from the official tree neither the driver which is actually 
also in 2.6.19-rc1 (=> DO NOT USE either 2.6.19-rc1), at least the 
official tree one week ago had this bug (I didn't verify later 
modifications).

-----------------------

In summary to get a working driver, I suggest in the following order of 
preferences:

1) Download and compile the kernel 2.6.18 and apply the very small patch 
to the file a800.c in "drivers/media/dvb/dvb-usb/a800.c" which I mention 
in point 2.) above. In this way you will get a working driver without 
any bugs (neither bug 2, 3, 4 of this list). Of course you need to 
compile all necessary modules, i.e. solve your actual problem.

2) If you stick with 2.6.17.x or 2.6.16.x than you can still apply the 
same patch to repair the bug 2 (cold-warm-state problem) but you still 
have the other bug 3 (the first-lock-problem) for which there are 
workarounds which are not very tough (essentially calling vlc in script 
with calling tzap before).

3) If you want to use the latest DVB-tree possible, you can take one 
which is at least 3-4 weeks old (if that is technically possible with 
the "hg"-download method ??) and combine it with every kernel version 
since 2.6.12 or 2.6.13 (I believe). I am actually using 2.6.19-rc1 but 
with the DVB v4l-tree from 12 August 2006 in which all bugs 2 and 3 are 
also repaired and bug 4 is not yet present. I believe the bug 4 appeared 
about 3-4 weeks ago, some time in september.

Greetings, Klaus.



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