[linux-dvb] Re: System load caused by I2C (was: Re: Re: Announcement: new saa7146 driver core for the av7110 dvb driver)

[Roberto Deza <rdeza@unav.es>]

Hi Michael, Holger and all,

At 00:14 21/12/2002 +0100, Michael Hunold wrote:

>In my current design, RPS0 is used for video capture, RPS1 is used for 
>vbi capture.
>
>If you can tell me for sure, that you never ever want to capture vbi (is 
>it re-inserted at all?) with a dvb card, then I can add a "use RPS1 for 
>DVB I2C access" mode.

@Michael:
A conditional compilation about the use of a RPS for I2C comunication 
would be great, to save this precious resource!, for other applications.

@Holger:
Would not be wise to implement some "poolling relaxation mechanism" on this
process that can repeat endlessly, if something goes wrong, 
progressively decreasing the fecuency at which its are retried?.

@all:
On past months, I've worked on a hardware & software patch to get access
to the full TS stream in Technotrend DVB "Premium" cards, without pass by
the AV711x restrictions and "boottleneck". Basically my approach is to 
connect the MPEG2 Demodulator outputs in the tuner, to the free Digital 
Video port in the SAA7146 (D1B), as is done on TT "budget" cards. On this
cards, two IC's are used to generate a pseudo VSYNC signal for the "frame
adquisition" of the TS packet(s) "lines"; my approach to avoid this IC's 
is to use the RPS1 to generate the pseudo VSYNC on the GPIO3 line (also 
free on all cards that I know, but maybe not on old Siemens DVB-C with the 
Analog module), which is then connected to D1B_VSYNC input. To make the 12 
connections need, I'm using a small PCB (5mm) wich is inserted between the 
tunner and the SAA7146 pins, so the soldering is more easy that using
discrete wires (the SAA7146 pins are at 0.65mm raster!). On the software
side, my patch do the setup of the RPS1 to generate the VSYNC and force
the driver to do all of the packet adquisition and filtering as it's done
on the budget cards, but preserving the other functions of the premium 
card.

My proyect is working on some degree and I wanted to publish it, for the
use by the interested, but there is some problem with "heavy use" :-(.
I can get the full TS without problems or selected PIDs, but when I start
VDR with my patched drivers, I get a Kernel Oops (Killing interrupt
handler...) inmediatelly :-(.

I don't have managed to find the reason or the cure and lattely I don't 
have the time to continue on it :-(. Ralph already had a first look at my 
patch, without find any "big error"; other member of the list also tries
to get it working. If someone is really interested on have a look at it
and don't fear to make hardware mods to the card! (if well done, the mods 
don't affect the behaviour of the card :-), I'm open to send the full 
documentation that I did.


Best regards:
--
Roberto Deza Asensio
Universidad de Navarra
Data Procesing Center
rdeza@unav.es


-- 
Info:
To unsubscribe send a mail to listar@linuxtv.org with "unsubscribe linux-dvb" as subject.