[linux-dvb] Strong signal, but no SNR?

Matthew Moore mdm at iinet.net.au
Sat Jun 18 08:30:32 CEST 2005


Hi all,

I'm having some *serious* difficulties geting my DVICO FusionHDTV cards to  
gain a signal.  I have had them working in the past but had to shelve the  
project owing to "senate" demands for time to be spent elsewhere :)

I'm now running a FC4 box with a recent kernel (see below) but for the  
life of me I can't figure out why I can't get a signal on most channels,  
and the channel that works doesn't give me a lock.  If you could shed any  
light I would be very appreciative.

Anyway, into the detail:

My kernel is: 2.6.11-1.1369_FC4 and I haven't modified the default options

The kernel seems to like the cards (/var/log/messages, but dmesg shows the  
same)
Jun 18 16:11:21 server kernel: Linux video capture interface: v1.00
Jun 18 16:11:21 server kernel: cx2388x v4l2 driver version 0.0.4 loaded
Jun 18 16:11:21 server kernel: ACPI: PCI Interrupt 0000:01:09.0[A] -> Link  
[LNKB] -> GSI 5 (level, low) -> IRQ 5
Jun 18 16:11:21 server kernel: cx88[0]: subsystem: 18ac:db00, board: DVICO  
FusionHDTV DVB-T1 [card=15,autodetected]
Jun 18 16:11:21 server kernel: cx88[0]/0: found at 0000:01:09.0, rev: 5,  
irq: 5, latency: 64, mmio: 0xd3000000
Jun 18 16:11:21 server kernel: cx88[0]/0: registered device video0 [v4l2]
Jun 18 16:11:21 server kernel: cx88[0]/0: registered device vbi0
Jun 18 16:11:21 server kernel: ACPI: PCI Interrupt 0000:01:0a.0[A] -> Link  
[LNKF] -> GSI 4 (level, low) -> IRQ 4
Jun 18 16:11:21 server kernel: cx88[1]: subsystem: 18ac:db00, board: DVICO  
FusionHDTV DVB-T1 [card=15,autodetected]
Jun 18 16:11:21 server kernel: cx88[1]/0: found at 0000:01:0a.0, rev: 5,  
irq: 4, latency: 64, mmio: 0xd5000000
Jun 18 16:11:21 server kernel: cx88[1]/0: registered device video1 [v4l2]
Jun 18 16:11:21 server kernel: cx88[1]/0: registered device vbi1
Jun 18 16:11:21 server kernel: cx2388x dvb driver version 0.0.4 loaded
Jun 18 16:11:21 server kernel: ACPI: PCI Interrupt 0000:01:09.2[A] -> Link  
[LNKB] -> GSI 5 (level, low) -> IRQ 5
Jun 18 16:11:21 server kernel: cx88[0]/2: found at 0000:01:09.2, rev: 5,  
irq: 5, latency: 64, mmio: 0xd4000000
Jun 18 16:11:21 server kernel: cx88[0]/2: cx2388x based dvb card
Jun 18 16:11:21 server kernel: DVB: registering new adapter (cx88[0]).
Jun 18 16:11:21 server kernel: DVB: registering frontend 0 (DVICO  
FusionHDTV DVB-T1)...
Jun 18 16:11:21 server kernel: ACPI: PCI Interrupt 0000:01:0a.2[A] -> Link  
[LNKF] -> GSI 4 (level, low) -> IRQ 4
Jun 18 16:11:21 server kernel: cx88[1]/2: found at 0000:01:0a.2, rev: 5,  
irq: 4, latency: 64, mmio: 0xd6000000
Jun 18 16:11:21 server kernel: cx88[1]/2: cx2388x based dvb card
Jun 18 16:11:21 server kernel: DVB: registering new adapter (cx88[1]).
Jun 18 16:11:21 server kernel: DVB: registering frontend 1 (DVICO  
FusionHDTV DVB-T1)...


The cards seem to be recognised in lspci:
01:09.0 Multimedia video controller: Conexant CX23880/1/2/3 PCI Video and  
Audio Decoder (rev 05)
01:09.2 Multimedia controller: Conexant CX23880/1/2/3 PCI Video and Audio  
Decoder [MPEG Port] (rev 05)
01:0a.0 Multimedia video controller: Conexant CX23880/1/2/3 PCI Video and  
Audio Decoder (rev 05)
01:0a.2 Multimedia controller: Conexant CX23880/1/2/3 PCI Video and Audio  
Decoder [MPEG Port] (rev 05)


And the modules are loaded when checking in lsmod:

Module                  Size  Used by
cx88_dvb                7621  0
cx8802                 12229  1 cx88_dvb
cx8800                 33741  0
cx88xx                 54112  3 cx88_dvb,cx8802,cx8800
video_buf_dvb           7109  1 cx88_dvb
cx22702                 5957  1 cx88_dvb
mt352                   6341  1 cx88_dvb
dvb_core               92393  1 video_buf_dvb
videodev                9537  2 cx8800,cx88xx
i2c_algo_bit            9289  1 cx88xx
v4l1_compat            13381  1 cx8800
v4l2_common             5825  1 cx8800
btcx_risc               4937  3 cx8802,cx8800,cx88xx
video_buf              23749  5 cx88_dvb,cx8802,cx8800,cx88xx,video_buf_dvb
ttpci_eeprom            2944  0
stv0297                 6416  0
mt312                   8068  0
cx24110                 7684  0
tda8083                 6148  0
l64781                  7172  0
dib3000mb              12928  0
tda1004x               13316  0
ves1820                 5892  0
stv0299                 9860  0
cx22700                 5892  0
sp8870                  7308  0
ves1x93                 6660  0
parport_pc             28933  1
lp                     13001  0
parport                40585  2 parport_pc,lp
autofs4                29253  2
rfcomm                 42333  0
l2cap                  30661  5 rfcomm
bluetooth              56133  4 rfcomm,l2cap
sunrpc                167813  1
ext3                  132553  1
jbd                    86233  1 ext3
dm_mod                 58101  0
video                  15941  0
button                  6609  0
battery                 9413  0
ac                      4805  0
md5                     4033  1
ipv6                  268097  24
ohci1394               41353  0
ieee1394              304441  1 ohci1394
uhci_hcd               35152  0
ehci_hcd               41037  0
ir_common               7493  1 cx88xx
tveeprom               13017  1 cx88xx
or51132                 9797  1 cx88_dvb
dvb_pll                 4677  3 cx88_dvb,cx22702,or51132
shpchp                 94405  0
i2c_core               21569  19  
cx88xx,cx22702,mt352,i2c_algo_bit,ttpci_eeprom,stv0297,mt312,cx24110,tda8083,l64781,dib3000mb,tda1004x,ves1820,stv0299,cx22700,sp8870,ves1x93,tveeprom,or51132
snd_hda_intel          17697  0
snd_hda_codec          54593  1 snd_hda_intel
snd_seq_dummy           3653  0
snd_seq_oss            37057  0
snd_seq_midi_event      9153  1 snd_seq_oss
snd_seq                62289  5  
snd_seq_dummy,snd_seq_oss,snd_seq_midi_event
snd_seq_device          8781  3 snd_seq_dummy,snd_seq_oss,snd_seq
snd_pcm_oss            51185  0
snd_mixer_oss          17857  1 snd_pcm_oss
snd_pcm               100169  3 snd_hda_intel,snd_hda_codec,snd_pcm_oss
snd_timer              33605  2 snd_seq,snd_pcm
snd                    57157  9  
snd_hda_intel,snd_hda_codec,snd_seq_oss,snd_seq,snd_seq_device,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_timer
soundcore              10913  1 snd
snd_page_alloc          9669  2 snd_hda_intel,snd_pcm
sk98lin               215324  1
floppy                 65269  0
xfs                   592529  1
exportfs                8897  1 xfs
raid5                  30401  1
xor                    14665  1 raid5
ata_piix                9413  6
libata                 47045  1 ata_piix
sd_mod                 20545  10
scsi_mod              148105  2 libata,sd_mod




Output from a Tzap on a channel that I *think* is showing a strong signal:

[root at server szap]# ./tzap -a1 "sbs hd"
using '/dev/dvb/adapter1/frontend0' and '/dev/dvb/adapter1/demux0'
reading channels from file '/root/.tzap/channels.conf'
tuning to 571500000 Hz
video pid 0x0066, audio pid 0x0067
status 00 | signal ffd0 | snr 0000 | ber 00000000 | unc 00000000 |
status 00 | signal ffd4 | snr 0000 | ber 00000000 | unc 00000000 |
status 00 | signal ffc2 | snr 0000 | ber 00000000 | unc 00000000 |
status 00 | signal ffc3 | snr 0000 | ber 00000000 | unc 00000000 |
status 00 | signal ffc1 | snr 0000 | ber 00000000 | unc 00000000 |
status 00 | signal ffc4 | snr 0000 | ber 00000000 | unc 00000000 |
status 00 | signal ffc6 | snr 0000 | ber 00000000 | unc 00000000 |
status 00 | signal ffcb | snr 0000 | ber 00000000 | unc 00000000 |
status 00 | signal ffcb | snr 0000 | ber 00000000 | unc 00000000 |
status 00 | signal ffda | snr 0000 | ber 00000000 | unc 00000000 |
status 00 | signal ffc4 | snr 0000 | ber 00000000 | unc 00000000 |

But note above - no SNR(!?).

Appologies for the verbosity, but thought it better to give all the  
relevant information I can think of rather than expecting people to ask  
for more..

Any ideas where to start looking?

Thanks,

Matt.




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