[mythtv-users] ivtv driver stop responding (Solution?)

Mike Isely isely at isely.net
Mon Mar 14 05:08:12 UTC 2005


On Sun, 13 Mar 2005, Karm may wrote:

   [...]

> kernel: irq 7: nobody cared (try booting with the
> "irqpoll" option.
> pvr kernel:  [<c013e0a0>] __report_bad_irq+0x2b/0x68
> kernel:  [<c013e169>] note_interrupt+0x73/0x96
> kernel:  [<c013d6cc>] __do_IRQ+0x1bd/0x249
> Mar 11 06:37:33 pvr kernel:  [<c0104e04>]
> do_IRQ+0x5e/0x7a
> kernel:  =======================
> kernel:  [<c01035b2>] common_interrupt+0x1a/0x20
> kernel:  [<c010103b>] default_idle+0x23/0x29
> kernel:  [<c010108f>] cpu_idle+0x1f/0x34
> kernel:  [<c03a5665>] start_kernel+0x16b/0x16d
> kernel: handlers:
> kernel: [<de950b83>] (ivtv_irq_handler+0x0/0x5b6
> ivtv])
> kernel: Disabling IRQ #7
> **************************************************
>
> I also notice that when I did "lspci -v" that my
> pvr-250 was using IRQ 7
>
> *** SOLUTION ****
> NOT GOOD TO DISABLE THE IRQ 7 ON THE PVR CARD...
> So I went in the BIOS->"PCI Settings" and set the IRQ
> specifically to 3 for my pvr 250 and IRQ 4 for my
> pvr-350.
>
> Conclusion:
> I have been up for 3 days without a reboot.  My 2 year
> old is now starting bring me the remote once again.
> ;-)
>
> ** QUESTIONS ***
> Why was the kernel "disabling" the PVR card?
> Is IRQ 7 supposed to be only used by parallel port
> operations?
>

I've seen this under different circumstances.  The PVR card is an innocent
victim in a foul-up involving IRQ7 and possibly your disabled parallel
port.

What is probably happening here is that some piece of hardware is holding
IRQ7 asserted.  The interrupt handler in the kernel then runs through all
registered handlers for that IRQ.  However none of the handlers reported
that they did anything useful (i.e. it wasn't "their" device asserting the
interrupt).  At that point the kernel is left with a stuck interrupt so it
had no choice but to disable it (otherwise the kernel will be wedged
forever trying to service an unservicable interrupt).  Unfortunately your
PVR card was on that interrupt and thus it lost its ability to signal the
ivtv driver and that killed the driver and then the mythtv backend.

The root cause is that something is jamming down IRQ7.  It may be the
printer port hardware on your system.  Disabling it in the BIOS will
likely prevent the kernel from seeing it and configuring a parallel port
driver for it - BUT the hardware may still be active and possibly
generating an interrupt.  That would set you up for this problem.  The
solution may be very simple: enable the parallel port in your BIOS setup
so that the Linux kernel will initialize a driver for it.

Reassigning the PVR card's IRQ away from IRQ7 gets the PVR card out of the
way, but you're probably still getting the stuck IRQ7 messages.

  -Mike

-- 
                        |         Mike Isely          |     PGP fingerprint
     Spammers Die!!     |                             | 03 54 43 4D 75 E5 CC 92
                        |   isely @ pobox (dot) com   | 71 16 01 E2 B5 F5 C1 E8
                        |                             |


More information about the mythtv-users mailing list