[mythtv-users] Excessive log messages from bt878 driver using Nebula card

John Winters john at sinodun.org.uk
Fri Aug 26 16:32:14 UTC 2005


I'm using a Nebula DVB-T card with the bt878 driver and kernel 2.6.8.
When MythTV is recording, the bt878 driver seems to generate several
hundred log messages per second, like this:

Aug 26 17:04:39 bluebox kernel: bt878(0): irq FDSR risc_pc=1eb84210
Aug 26 17:04:39 bluebox last message repeated 523 times
Aug 26 17:04:39 bluebox kernel: bt878(0): irq FDSR risc_pc=1eb84010

Note - all that in less than a second.

Looking at the code for the bt878 driver it appears that turning off
"bt878_verbose" might reduce this, but is it normal?  It seems odd to
want to produce quite so many log messages.

This may be related to another problem which I have.  Every few days
there is an interrupt which doesn't get handled, resulting in the kernel
disabling the interrupt and the card then stops working.  Could it be
that the driver fails to handle the interrupt because it's spending too
much time generating log messages?

Aug 25 20:07:35 bluebox kernel: bt878(0): irq FDSR risc_pc=1e156008
Aug 25 20:07:35 bluebox last message repeated 408 times
Aug 25 20:07:35 bluebox kernel: irq 10: nobody cared!
Aug 25 20:07:35 bluebox kernel:  [__report_bad_irq+49/115]
__report_bad_irq+0x31/0x73
Aug 25 20:07:35 bluebox kernel:  [note_interrupt+76/111] note_interrupt
+0x4c/0x6f
Aug 25 20:07:35 bluebox kernel:  [do_IRQ+146/249] do_IRQ+0x92/0xf9
Aug 25 20:07:35 bluebox kernel:  [common_interrupt+24/32]
common_interrupt+0x18/0x20
Aug 25 20:07:35 bluebox kernel: handlers:
Aug 25 20:07:35 bluebox kernel: [__crc_fs_overflowgid+176499/7468671]
(bttv_irq+0x0/0x2c0 [bttv])
Aug 25 20:07:35 bluebox kernel: [__crc_tcp_send_synack+882430/982184]
(bt878_irq+0x0/0x180 [bt878])
Aug 25 20:07:35 bluebox kernel: [__crc_fs_overflowgid+1572458/7468671]
(ohci_irq_handler+0x0/0x612 [ohci1394])
Aug 25 20:07:35 bluebox kernel: [__crc_fs_overflowgid+1896061/7468671]
(usb_hcd_irq+0x0/0x4e [usbcore])
Aug 25 20:07:35 bluebox kernel: Disabling IRQ #10

Any advice appreciated.

Regards,
John

P.S.  I'd appreciate advice too on how to set the "bt878_verbose"
parameter to 0 without changing the source and recompiling.  I've tried
putting:

bt878 "bt878_verbose=0"

in /etc/modules, but that produces this error message in the system log.

Aug 26 06:52:30 bluebox kernel: bt878: Unknown parameter
`"bt878_verbose'





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