[linux-dvb] Pinnacle PCTV Sat HDTV Pro USB (PCTV452e)

Manu Abraham abraham.manu at gmail.com
Thu Oct 25 05:53:28 CEST 2007


garlicdevel at ntlworld.com wrote:
>>> but I think the older driver could be better at the moment as with the newer 
>> driver the device doesn't appear to initialize for the stb0899
>> hmm, i have checked both and they don't differ.
> 
> there seems to be some more checks in the newer driver to make sure the device is in the right state
> also looking at one of the newer budget devices that's using it, there seems to be a whole bunch of defines added into the config structure
> I'm not sure if these are being used just yet (or if so what for)
> but I'm keeping my options open by trying things against both for now just to be sure
> 
> 
>> you are "initialising" STB0899_DISFIFO in line 51 with 0x00.
>> this byte will be sent out after frontend_init() on the first diseqc command.
> 
> sorry about that
> the win driver appears to fill in a default set of values when the device is plugged in
> this is what I've used in the data structure
> although if the stb driver doesn't change these again afterwards in the same way the win driver does, then this won't work right
> I'll need to take a closer look at the values that are being set after the initial plugin of the device
> looking at the logs for this one, it seems to be going mostly from 00 to e2, with 10, 38, f0 near the end of the log

You are right. In fact this is a FIFO, but initially it is initialized to 0x00 to avoid 
garbage in the output. You are right as well that the FIFO is modified later on 
at run time, which you can see it in the driver. The FIFO is transferred only 
when the precharge is discharged, till then whatever you have in the FIFO is 
of no concern.

You can see the FIFO being modified at runtime here (contrary to your claim 
that the stb0899 driver doesn't modify the FIFO, well if it wouldn't have, then 
there wouldn't have been any diseqc commands sent)

http://jusst.de/hg/multiproto/file/2c1aa7b57779/linux/drivers/media/dvb/frontends/stb0899_drv.c
line #687 before the discharge

Manu




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