[linux-dvb] Pundit-R Avermedia 771 DVB IRQ lockup

[Stephen Greszczyszyn]

Hi there,

I have an Asus Pundit-R barebones which I'm using with
Ubuntu Linux (kernel 2.6.12-10-686) and Avermedia 771
DVB-T card and MythTV as a PVR.  

I recently upgraded to MythTV0.19 and had some
problems with tuning the channels.

After looking closer in the logs, I see that I am
getting IRQ lockups:

syslog:
Mar 22 19:05:57 localhost kernel: [4295474.720000]
bt878(0): irq FBUS risc_pc=366f5008
Mar 22 19:05:57 localhost last message repeated 71
times
Mar 22 19:05:57 localhost kernel: [4295474.720000]
bt878(0): IRQ lockup, cleared int mask

dmesg
[4295521.312000] bt878(0): irq FBUS risc_pc=3677b008
[4295521.312000] bt878(0): irq FBUS risc_pc=3677b008
[4295521.312000] bt878(0): IRQ lockup, cleared int
mask

It looks like the Avermedia card is sharing IRQ 17
with the ATI onboad sound.  I changed the Avermedia
771 card to the only other PCI slot on the riser card
and it gives it the same IRQ as the ATI onboard
graphics card:

sgreszcz at myth:~$ cat /proc/interrupts
           CPU0
  0:    1867815    IO-APIC-edge  timer
  8:          1    IO-APIC-edge  rtc
 14:      16384    IO-APIC-edge  ide0
 15:      80414    IO-APIC-edge  ide1
 16:     177886   IO-APIC-level  yenta,
radeon at pci:0000:01:05.0
 17:       8779   IO-APIC-level  bttv0, bt878, ATI IXP
 18:      11332   IO-APIC-level  ohci1394, eth0
 19:      14676   IO-APIC-level  ohci_hcd:usb1,
ohci_hcd:usb2, ehci_hcd:usb3
 21:          1   IO-APIC-level  acpi
NMI:          0
LOC:    1867223
ERR:          0
MIS:          0

I have been reading that the Avermedia 771 does not
like sharing IRQs.  Is there any way to prevent this
IRQ lockup from happening?

Thanks!