[linux-dvb] Re: dvb-ip : Which TwinHan's card is better ?

[olivier <bitmap@pan.homelinux.com>]

Johannes Stezenbach <js@linuxtv.org> disait récemment :

> bt878_find_by_dvb_adap() is working fine, but the frontend is not
> detected, i.e. dst_check_ci() fails. Probably some of the many magic
> msleep()s aren't entirely correct. The code that Twinhan released
> does thing differently but similarly magic, and I've no time to
> do experiments to find out.
> 
> Johannes

Yes, I've found that the problem may be in the file
linux/drivers/media/video/bttv-i2c.c, in bttv_i2c_xfer(). (called by
dst_check_ci).

In bttv_i2c_wait_done(), BT848_INT_RACK is reset when BT848_INT_I2CDONE 
is set.  (according to the  doc, it means  that the receiver  does not
acknowledge).  But  I think  it's  not  only  that, Twinhan's  I2C  is
strange, as Manu said.

In fact,  I tested my  card on three  computers, with same  kernel and
drivers. Two of them don't want  to know anything (see the log below),
and in  the last the  card works most  of the time, sometimes  not and
I've got to reload modules.

"Jake L. Wegman" <jake@ultrex.com> disait récemment :

> I also am experiencing a "Frontend" issue with the Twinhan VP-1020 (old blue
> circuit board).  The current (10/8/04) CVS dvb-kernel drivers will not find
> a valid frontend.
> 
> Any enlightening information, or ideas of how I can best help, please let me
> know.
> Regards,
> Jake

This looks  like exactly the same  problem.  Does it  always work with
2.6.9 and  never with 2.6.10,  or randomly ?  This is weird,  and very
annoying...

Below the syslog, with a 2.6.8.1 kernel and CVS dvb drivers.

---
Nov 8 12:23:35 obelix kernel: bt878(0): Bt878 (rev 17) at 00:13.1, irq: 11, latency: 64, memory: 0xec003000
Nov 8 12:23:35 obelix kernel: dstbudget: Ignoring new-style parameters in presence of obsolete ones
Nov 8 12:23:36 obelix kernel: dvb_bt8xx: identified card0 as bttv0
Nov 8 12:23:36 obelix kernel: DVB: registering new adapter (bttv0). 
Nov 8 12:23:36 obelix kernel: write_dst writing 0x00 0x06 0x00 0x00 0x00 0x00 0x00 0xfa
Nov 8 12:23:36 obelix kernel: bt-i2c: ERR: -5
Nov 8 12:23:36 obelix kernel: write_dst: write_dst error (err == -5, len == 0x08, b0 == 0x00)
Nov 8 12:23:37 obelix kernel: bt-i2c: ERR: -5
Nov 8 12:23:37 obelix kernel: write_dst: write_dst error (err == -5, len == 0x08, b0 == 0x00)
Nov 8 12:23:38 obelix kernel: bt-i2c: ERR: -5
Nov 8 12:23:38 obelix kernel: write_dst: write_dst error (err == -5, len == 0x08, b0 == 0x00)
Nov 8 12:23:40 obelix kernel: bt-i2c: ERR: -5
Nov 8 12:23:40 obelix kernel: write_dst: write_dst error (err == -5, len == 0x08, b0 == 0x00)
Nov 8 12:23:45 obelix kernel: dst_check_ci: write not successful, maybe no card? 
Nov 8 12:23:45 obelix kernel: dvb-bt8xx: A frontend driver was not found for device 109e/0878 subsystem 1822/0001