Re: Sound problems - CD Player not working

[sungod <sungod atdot org>]

Scott Haug (eldamitri@hotmail.com)'s email of 07/28/99 11:10 said:

>I've checked to make 
>sure that all the appropriate lines/volumes are turned up and unmuted.  
>Linux cd apps will recognize the cd, will look it up correctly on cddb, will 
>play it (time advances on the player, sound comes out of the cdrom drive 
>itself via the headphone jack), but no sound comes out of the soundcard.  I 
>haven't checked to see if write permissions are set on my /dev/hdc file (as 
>another poster suggested), but I don't understand why that would affect 
>things.

It affects things because not only does the circuitry in your CD ROM 
drive do the D->A conversion, as I previously posted, but it also handles 
the disc detection and transport as well. That is, when your computer 
sends it a signal to "play," it is actually a circuit in the CD ROM drive 
that makes it play, not the software.

You could, theoretically, hook up an LCD screen, simple microcontroller, 
power supply, and a few pushbuttons (if you knew where to solder) to a 
standard CD-ROM drive and have a CD walkman, because all the basic logic 
is built into the hardware.

All the software is really doing is behaving like that LCD screen and 
pushbuttons. Consequently, you need to make sure you can write to the CD 
ROM drive in order to pass the information, "play!" or "stop!" or "fast 
forward!" Without a+w permissions on the drive itself, the kernel will 
not allow these messages to be sent to the drive.

Yes, I've oversimplified a bit, but hopefully you understand how it works 
so you can troubleshoot a little more effectively on your end. If it 
works under Windows already, I can just about guarantee that the problem 
is with the permissions on your drive, as has been mentioned. Give it a 
shot.

-- 
"True riches only increase." -R. Buckminster Fuller
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