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

Al McIntosh junkmail at allanmcintosh.com
Mon Jan 9 00:05:25 UTC 2006


Michael Haan wrote:

> On 1/8/06, *Al McIntosh* <junkmail at allanmcintosh.com 
> <mailto:junkmail at allanmcintosh.com>> wrote:
>
>     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)
>
>
> I'm currently having similar issues with hdtv.  Can you try seeking to 
> just before the freeze, then jumping ahead to pass it?  For me, this 
> results in no freeze, but a loss of sound.


I have been able to jump past the problem spots and continue watching. I 
do not experience the sound loss though.

Also, just to check I seeked just before the freeze and watched right 
over it. It appears the reboot has reset something.







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