[mythtv-users] DMA buffer DeQueue failed!

Gary Raposo gary at raposo.ca
Mon Nov 3 02:01:46 EST 2003


Hi guys,

Been working on this all night and making absolutely no progress.  It's 2am 
so I thought I'd bounce it off you guys and try some more tomorrow.

MythTV 0.12
Latest IVTV CVS tarball
ALSA 0.9.8
RedHat Linux 9

Asus Pundit 2.4GHz/512MB/120GB/2xPVR250

My problems started when I attempted to upgrade IVTV in order to get some 
better quality out of my cable line.  The upgrade seemed to have worked 
just fine BUT I started noticing dropped frames... very noticeable!  Whole 
chunks of the stream appeared to have been chopped right out.  In any case, 
/var/log/messages logs the following errors continuously while 
recording.  The CPU is sitting at almost 99% idle and there is no paging 
during this time yet I still log buffer errors.

...
Nov  3 01:51:02 mythtv kernel: ivtv: Nov  3 01:51:02 mythtv kernel: ivtv: 
DMA buffer DeQueue failed! got 1, want 1
Nov  3 01:51:02 mythtv kernel: ivtv: DEC: free_q: 0 elements
Nov  3 01:51:02 mythtv kernel: ivtv: DEC: dma_q: 0 elements
Nov  3 01:51:02 mythtv kernel: ivtv: DEC: full_q: 100 elements
Nov  3 01:51:20 mythtv kernel: ivtv: DMA buffer DeQueue failed! got 1, want 1
Nov  3 01:51:20 mythtv kernel: ivtv: DEC: free_q: 0 elements
Nov  3 01:51:20 mythtv kernel: ivtv: DEC: dma_q: 0 elements
Nov  3 01:51:20 mythtv kernel: ivtv: DEC: full_q: 100 elements
Nov  3 01:51:38 mythtv kernel: ivtv: DMA buffer DeQueue failed! got 1, want 1
Nov  3 01:51:38 mythtv kernel: ivtv: DEC: free_q: 0 elements
Nov  3 01:51:38 mythtv kernel: ivtv: DEC: dma_q: 0 elements
Nov  3 01:51:38 mythtv kernel: ivtv: DEC: full_q: 100 elements
Nov  3 01:51:56 mythtv kernel: ivtv: DMA buffer DeQueue failed! got 1, want 1
Nov  3 01:51:56 mythtv kernel: ivtv: DEC: free_q: 0 elements
Nov  3 01:51:56 mythtv kernel: ivtv: DEC: dma_q: 0 elements
Nov  3 01:51:56 mythtv kernel: ivtv: DEC: full_q: 100 elements
Nov  3 01:52:15 mythtv kernel: ivtv: DMA buffer DeQueue failed! got 1, want 1
Nov  3 01:52:15 mythtv kernel: ivtv: DEC: free_q: 0 elements
Nov  3 01:52:15 mythtv kernel: ivtv: DEC: dma_q: 0 elements
Nov  3 01:52:15 mythtv kernel: ivtv: DEC: full_q: 100 elements
Nov  3 01:52:33 mythtv kernel: ivtv: DMA buffer DeQueue failed! got 1, want 1
Nov  3 01:52:33 mythtv kernel: ivtv: DEC: free_q: 0 elements
Nov  3 01:52:33 mythtv kernel: ivtv: DEC: dma_q: 0 elements
Nov  3 01:52:33 mythtv kernel: ivtv: DEC: full_q: 100 elements got 1, want 1
Nov  3 01:51:02 mythtv kernel: ivtv: DEC: free_q: 0 elements
Nov  3 01:51:02 mythtv kernel: ivtv: DEC: dma_q: 0 elements
Nov  3 01:51:02 mythtv kernel: ivtv: DEC: full_q: 100 elements
Nov  3 01:51:20 mythtv kernel: ivtv: DMA buffer DeQueue failed! got 1, want 1
Nov  3 01:51:20 mythtv kernel: ivtv: DEC: free_q: 0 elements
Nov  3 01:51:20 mythtv kernel: ivtv: DEC: dma_q: 0 elements
Nov  3 01:51:20 mythtv kernel: ivtv: DEC: full_q: 100 elements
Nov  3 01:51:38 mythtv kernel: ivtv: DMA buffer DeQueue failed! got 1, want 1
Nov  3 01:51:38 mythtv kernel: ivtv: DEC: free_q: 0 elements
Nov  3 01:51:38 mythtv kernel: ivtv: DEC: dma_q: 0 elements
Nov  3 01:51:38 mythtv kernel: ivtv: DEC: full_q: 100 elements
Nov  3 01:51:56 mythtv kernel: ivtv: DMA buffer DeQueue failed! got 1, want 1
Nov  3 01:51:56 mythtv kernel: ivtv: DEC: free_q: 0 elements
Nov  3 01:51:56 mythtv kernel: ivtv: DEC: dma_q: 0 elements
Nov  3 01:51:56 mythtv kernel: ivtv: DEC: full_q: 100 elements
Nov  3 01:52:15 mythtv kernel: ivtv: DMA buffer DeQueue failed! got 1, want 1
Nov  3 01:52:15 mythtv kernel: ivtv: DEC: free_q: 0 elements
Nov  3 01:52:15 mythtv kernel: ivtv: DEC: dma_q: 0 elements
Nov  3 01:52:15 mythtv kernel: ivtv: DEC: full_q: 100 elements
Nov  3 01:52:33 mythtv kernel: ivtv: DMA buffer DeQueue failed! got 1, want 1
Nov  3 01:52:33 mythtv kernel: ivtv: DEC: free_q: 0 elements
Nov  3 01:52:33 mythtv kernel: ivtv: DEC: dma_q: 0 elements
Nov  3 01:52:33 mythtv kernel: ivtv: DEC: full_q: 100 elements
...

Has anyone ever seen this?  No luck googling these errors.  Not too sure if 
this is something I should take up on the IVTV list or not.

Thanks.

Gary Raposo                                              gary at raposo.ca
Eschew obfuscation...                              http://www.raposo.ca



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