[linux-dvb] Re: Mantis VP-1027/VP-1033/VP-1034/VP-2033/VP-3033

Marko Ristola marko.ristola at kolumbus.fi
Fri Oct 13 19:50:09 CEST 2006


I didn't read emails for a few days.
I don't have any specs for the hardware either.

I'll try to figure out that what is the problem.

I think that when the DMA transfer starts, cu1216_set_parameters() 
should not be called at all.
 The drivers should just keep on with the data transfer.

One possible fix might be that cu1216_set_parameters()
would set the fixed values: they should not be changed during the data 
transfer.
Maybe reading other similar drivers help with this.

The other thing is that is it a bug or okay when the cu1216 is 
nonresponsive during the data transfer.

Manu, How is this supposed to work?

Regards,
Marko

Pauli Borodulin kirjoitti:
> Pauli Borodulin wrote:
>   
>> [...]
>> The problem is: In the beginning the driver is able to communicate with
>> cu1216 using I2C. For example, the driver is able to check that the
>> demodulator is there using cu1216_readreg(). As soon as DMA is started (you
>> get "mantis start feed & dma" in your kernel log), all i2c reading and
>> writing fails. Every read returns 0. I have not yet found out why. You can
>> verify this by adding
>> [...]
>>     
>
> I made a quick and dirty hack and commented out the contents of the
> functions mantis_dma.c/mantis_dma_start() and mantis_dma.c/mantis_dma_stop()
> and now I2C seems to works ok. This will totally break the driver, so it's
> not a fix. I did it because I was curios whether it would make any
> difference, and it did. I then tried uncommenting lines in
> mantis_dma_start() one by one starting from the beginning, and found out
> that the line
>
>     mmwrite(MANTIS_GPIF_RDWRN, MANTIS_GPIF_ADDR);
>
> was the one that triggered the bug. I have no knowledge on the hardware in
> question (I don't have any datasheets etc.), so I have no idea what I should
> do next. There's also some bugs in the cu1216 driver, but it's no use to
> debug them before the DMA(?) problem is fixed.
>
>
> Br,
>   
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