[linux-dvb] cx88-dvb card not generating interrupts?

davidm davidm_ltv at davidmonro.net
Tue Mar 13 13:45:38 CET 2007


I've got a bit of an odd problem. I'm trying to run a cx88-dvb board 
(KWorld/VStream XPert DVB-T) in a cobalt raq550. (Yes, I'm probably 
mad). The card works fine in other boxes, but in this box doesn't 
generate any interrupts (I get "cx88[0]/2-mpeg: cx8802_timeout" again 
and again in the logs, and /proc/interrupts shows 0 for the interrupt 
count). The lspci output looks fine, and I've tested another 
multifunction card (dual-channel scsi) and it gets mapped to the same 
IRQ and works fine. I'm wondering if there's something the driver needs 
to do to enable generation of interrupts or something like that, which 
would be done by the bios on a 'normal' machine but doesn't happen on 
the cobalt?

Running tzap actually gives output as if the card was working fine:

tzap ABC2
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
tuning to 781500000 Hz
video pid 0x090a, audio pid 0x090c
status 00 | signal 4a3f | snr 0000 | ber 00000000 | unc 00000000 |
status 1f | signal ec7f | snr 9c9c | ber 00000000 | unc 00000000 | 
FE_HAS_LOCK
status 1f | signal ed4f | snr 9c9c | ber 00000000 | unc 00000000 | 
FE_HAS_LOCK
status 1f | signal ed1f | snr 9b9b | ber 00000000 | unc 00000000 | 
FE_HAS_LOCK
status 1f | signal ed2f | snr 9c9c | ber 00000000 | unc 00000000 | 
FE_HAS_LOCK
status 1f | signal edbf | snr 9c9c | ber 00000000 | unc 00000000 | 
FE_HAS_LOCK
....

so clearly at least some of the card is working!

(if it wasn't for the scsi card working, I'd be assuming the interrupt 
routing was simply completely borked for multifunction cards, but since 
the scsi card works fine I'm rather puzzled).

Kernel is a kernel.org 2.6.20 with the minimal patches to get the cobalt 
working (for the people who haven't had the pleasure of meeting one of 
these machines, it does not have a regular PC bios; there's a very low 
level bootstrap in rom which then loads a modified and cut-down linux 
2.4 kernel out of flash, which then loads the proper kernel off disk and 
boots it).

Cheers,

	David





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