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

Pauli Borodulin Pauli at Borodulin.fi
Tue Oct 10 20:19:36 CEST 2006


Marko Ristola wrote:
> [...]
> Sleep function does not seem to make any difference: even though
> kaffeine pauses
> by doing sleep, it blinks (kaffeine uses xine frontend).
> Could the problem be 64bit DMA related?
> I don't have a 32bit distribution to try.
> I have NForce4 chipset. Here is a Kaffeine screen probe:

> Oct  9 21:53:37 koivu kernel: [cu1216_set_parameters]: accept Iq=1,
> uc_Gain=3, errRate=15
> Oct  9 21:53:37 koivu kernel: [cu1216_set_parameters]: goto ret with
> Iq=1, Gain=3, errRate=15
> Oct  9 21:53:37 koivu kernel: [cu1216_set_parameters]: status = 0
> Oct  9 21:53:37 koivu kernel: [cu1216_read_status]: status = 31, sync=47
> Oct  9 21:53:37 koivu kernel: mantis start feed & dma
> Oct  9 21:53:37 koivu kernel: [cu1216_read_status]: status = 0, sync=0

I just spent three hours debugging my problem and I have to admit that your
problem looks the same as mine. My system is 32-bit, so this problem doesn't
seem to be 32/64-problem.

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

    /* check if i2c stuff still works */
    if ((cu1216_readreg(state, AC_IDENTITY_IND) & 0xf0) != 0x70) {
        printk("I2C READING FAILED.\n");

in the beginning of cu1216_set_parameters() (but after *state is acquired,
of course). The same test is in cu1216.c/cu1216_attach() which is always run
before any DMA is initiated. When executed there, it correctly gets value
0x70, but anytime dma is active, all i2c reads return 0.

Pauli Borodulin <pauli at borodulin.fi>
gsm. +358 (0) 44 5555 381

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