[mythtv-users] ALSA, intel8x0 and WriteAudio: buffer underrun

Al McIntosh junkmail at allanmcintosh.com
Sun Jan 8 22:46:31 UTC 2006


Michael T. Dean wrote:

> Al McIntosh wrote:
>
>> I have an AMD Sempron 2800+, MSI nForce4 K8N Neo3 with onboard nVidia 
>> Corporation CK804 AC'97 Audio Controller. I have been experiencing 
>> problems with mythfronted freezing during playback of recorded shows. 
>> I have to kill it but it becames defunct.
>>
>> I am using alsa 1.0.10 and myth 0.18.1
>>
>> I believe it's the sound card because of the following mythfrontend 
>> output appears when the crash occurs:
>>
>> 006-01-07 14:27:19.240 prebuffering pause
>
>
> Sure it's not an I/O issue?  Perhaps the buffer underrun on the audio 
> was due to the lack of data caused by prebuffering pauses.  Were you 
> playing HDTV?  Problem with your hard drives or network (if using a 
> network filesystem or Myth streaming)?
>


Not HDTV. The files are all on the local filesystem, on a 3 or 4 month 
old Maxtor 6L250R0, ATA DISK.

I have not seen any evidence of drive failure. Not to say this is not 
the culpret.
DMA is on.

Yesterday, on my mythfrontend/backend/filserver machine, mythfrontend 
froze at 00:23:46 of a recording. I killed the frontend, it became 
defunct. I started another frontend, seeked ahead to 00:23:46 and the 
second mythfrontend froze and became defunct also. I went to another PC 
and started mythfrontend, seeked ahead to 00:23:46 and mythfrontend 
froze and became defunct. From the second PC I tried to play the file 
directly using mplayer via nfs and mplayer froze at 00:23:46. I had to 
kill mplayer which became defunct. After a reboot, I managed to play the 
file straight through.



Not sure anyone can make sense of this call trace:
Call Trace:
Jan  7 14:24:03 nelson kernel:  [<c013b917>] add_to_page_cache+0x41/0x83
Jan  7 14:24:03 nelson kernel:  [<c0179cd5>] mpage_readpages+0xed/0x13e
Jan  7 14:24:03 nelson kernel:  [<f88b9054>] ext3_get_block+0x0/0x90 [ext3]
Jan  7 14:24:03 nelson kernel:  [<c013f732>] rmqueue_bulk+0x74/0x7e
Jan  7 14:24:03 nelson kernel:  [<f88b9e2d>] ext3_readpages+0x0/0x15 [ext3]
Jan  7 14:24:03 nelson kernel:  [<c0141e6a>] read_pages+0x2a/0xf7
Jan  7 14:24:03 nelson kernel:  [<f88b9054>] ext3_get_block+0x0/0x90 [ext3]
Jan  7 14:24:03 nelson kernel:  [<c013fd81>] __alloc_pages+0xe8/0x407
Jan  7 14:24:03 nelson kernel:  [<c030a471>] _spin_unlock_irq+0x5/0x7
Jan  7 14:24:03 nelson kernel:  [<c0142077>] 
__do_page_cache_readahead+0x140/0x145
Jan  7 14:24:03 nelson kernel:  [<c014218f>] 
blockable_page_cache_readahead+0x53/0xbc
Jan  7 14:24:03 nelson kernel:  [<c0142253>] make_ahead_window+0x5b/0x9a
Jan  7 14:24:03 nelson kernel:  [<c0142317>] page_cache_readahead+0x85/0x15f
Jan  7 14:24:03 nelson kernel:  [<c013c204>] 
do_generic_mapping_read+0x3be/0x44b
Jan  7 14:24:03 nelson kernel:  [<c013c415>] 
__generic_file_aio_read+0xaa/0x1f6
Jan  7 14:24:03 nelson kernel:  [<c013c291>] file_read_actor+0x0/0xda
Jan  7 14:24:03 nelson kernel:  [<c0116de0>] activate_task+0x59/0x68
Jan  7 14:24:03 nelson kernel:  [<c013c59f>] generic_file_aio_read+0x3e/0x4f
Jan  7 14:24:03 nelson kernel:  [<c01584f2>] do_sync_read+0xbf/0x11a
Jan  7 14:24:03 nelson kernel:  [<c0130cc4>] futex_requeue+0x142/0x2cb
Jan  7 14:24:03 nelson kernel:  [<c012d9fe>] 
autoremove_wake_function+0x0/0x37
Jan  7 14:24:03 nelson kernel:  [<c0158433>] do_sync_read+0x0/0x11a
Jan  7 14:24:03 nelson kernel:  [<c01585ed>] vfs_read+0xa0/0x158
Jan  7 14:24:03 nelson kernel:  [<c015895a>] sys_read+0x41/0x6a
Jan  7 14:24:03 nelson kernel:  [<c0102ea1>] syscall_call+0x7/0xb
Jan  7 14:24:03 nelson kernel: Code: 84 85 db 74 30 83 03 01 8b 04 24 89 
44 ab 04 0f a3 ab 04 01 00 00 19 c0 85 c0
 75 68 0f a3 ab 0c 01 00 00 19 c0 31 c9 85 c0 74 b1 <0f> 0b 14 01 5c c7 
32 c0 eb a7 8b 0c 24 8b 54 24 08 89 4a 08
31
Jan  7 14:24:03 nelson kernel:  <0>BUG: rwlock cpu recursion on CPU#0, 
kswapd0/189, d82de710 (Tainted: PF    )
Jan  7 14:24:03 nelson kernel:  [<c01d1b4e>] _raw_write_lock+0x48/0x58
Jan  7 14:24:03 nelson kernel:  [<c0145cc1>] shrink_list+0x190/0x480
Jan  7 14:24:03 nelson kernel:  [<c0144f0f>] __pagevec_lru_add+0xab/0xba
Jan  7 14:24:03 nelson kernel:  [<c0144dd2>] __pagevec_release+0x15/0x1d
Jan  7 14:24:03 nelson kernel:  [<c014615e>] shrink_cache+0xe7/0x29a
Jan  7 14:24:03 nelson kernel:  [<c0146781>] shrink_zone+0x88/0xd6
Jan  7 14:24:03 nelson kernel:  [<c0146bc3>] balance_pgdat+0x213/0x3d5
Jan  7 14:24:04 nelson kernel:  [<c0146e50>] kswapd+0xcb/0x109
Jan  7 14:24:04 nelson kernel:  [<c012d9fe>] 
autoremove_wake_function+0x0/0x37
Jan  7 14:24:04 nelson kernel:  [<c0146d85>] kswapd+0x0/0x109
Jan  7 14:24:04 nelson kernel:  [<c0101301>] kernel_thread_helper+0x5/0xb
Jan  7 14:24:48 nelson lircd-0.8.0-CVS[6924]: removed client
Jan  7 14:24:49 nelson kernel: audit(:0): major=252 name_count=0: 
freeing multiple contexts (1)





 




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