Can't enable DMA on cd rom drive

Question

Hey,
How could I get my CD ROM drive, recognized as /dev/sr0, to get Direct Memory Access enabled?
The reason for this is when I use mplayer to read from an audio CD, the cache gets emptied pretty fast (and without it, audio is too choppy to listen to), and I'm guessing enabling DMA will make it run smoothly.
After some searching I tried 'hdparm':
hdparm -d /dev/sr0
And I get:
/dev/sr0:
HDIO_GET_DMA failed: Inappropriate ioctl for device
Any help would be appreciated!

Answer 1

Thanks for the swift reply.
Here's the result:
[pilgrim@archie ~]$ mplayer cdda:// -cache 8192
MPlayer SVN-r34426-4.6.2 (C) 2000-2011 MPlayer Team
181 audio & 384 video codecs
mplayer: could not connect to socket
mplayer: No such file or directory
Failed to open LIRC support. You will not be able to use your remote control.
Playing cdda://.
Can't open CDDA device.
Failed to open cdda://.
Exiting... (End of file)
When I manage to get it playing I'm running:
[pilgrim@archie ~]$ sudo mplayer -cdrom-device /dev/sr0 cdda:// -cache 8192
MPlayer SVN-r34426-4.6.2 (C) 2000-2011 MPlayer Team
181 audio & 384 video codecs
mplayer: could not connect to socket
mplayer: No such file or directory
Failed to open LIRC support. You will not be able to use your remote control.
Playing cdda://.
Found audio CD with 20 tracks.
Cache fill: 0.00% (0 bytes)
Track 1
Cache fill: 19.91% (1669920 bytes)
rawaudio file format detected.
Cache not responding! [performance issue]
==========================================================================
Opening audio decoder: [pcm] Uncompressed PCM audio decoder
AUDIO: 44100 Hz, 2 ch, s16le, 1411.2 kbit/100.00% (ratio: 176400->176400)
Selected audio codec: [pcm] afm: pcm (Uncompressed PCM)
==========================================================================
[AO OSS] audio_setup: Can't open audio device /dev/dsp: No such file or directory
AO: [alsa] 48000Hz 2ch s16le (2 bytes per sample)
Video: no video
Starting playback...
A: 8.7 (08.7) of 4454.4 ( 1:14:14.3) 0.6% 13%
Notice how just 8 seconds in, the cache dropped from 20 to 13, and it won't refill... it just keeps emptying until I get the choppy behavior again. I think making the cache huge would be a workaround but maybe there's a better solution.
Last edited by pilgrim689 (2011-12-26 19:33:38)