Re: Strange things happen when reading from CD-ROM

[Christoph Groth <cgroth@gmx.net>]

Steven Dickenson <steven@usermail.com> writes:

> > It would be mechanically impossible to connect all the drives in
> > any other way using the chassis and cables I have.
> 
> 36" IDE cables are your friend.... ;)

Isn't there a severe restriction of the length of IDE-cables?  At
least for UDMA?

> > I will try it, but the problem doesn't seem to be interference, as
> > the sound output really gets _slower_ and not just noisy.
> 
> Interesting.  I missed that on the first post.  It sounds like a
> CPU/Resource problem.  What are the DMA settings for your sound
> card?  Does it use a DMA channel?

Yes, it's a Gravis Ultrasound PnP ISA Soundcard.  These are the
options I use:

options snd-card-interwave snd_index=1 snd_id=CARD_1 snd_port=0x220 snd_irq=11 s nd_dma1=5 snd_dma1_size=128 snd_dma2=6 snd_dma2_size=128 snd_midi=0

~$ cat /proc/dma
 4: cascade
 5: GFA1/CS4231 record
 6: CS4231 playback
~$ cat /proc/interrupts 
           CPU0       
  0:      58406          XT-PIC  timer
  1:       2729          XT-PIC  keyboard
  2:          0          XT-PIC  cascade
  4:       4243          XT-PIC  serial
  8:          1          XT-PIC  rtc
 10:          0          XT-PIC  eth0
 11:      19467          XT-PIC  InterWave
 13:          1          XT-PIC  fpu
 14:      33605          XT-PIC  ide0
 15:      16729          XT-PIC  ide1
NMI:          0

> This definitley lends credence to the software problem theory.
> Unfortunatley, my Linux skills are nothing compared to my general
> hardware skills, so I can't offer you too many suggestions on
> hardware tuning and troubleshooting drivers under Linux.  Have you
> tried compiling your own kernel?  Did you mention what version
> you're using, I can't remember.  You could always try and move to
> 2.4.  I'm running 2.4.2 under both sid and potato (with a few other
> upgraded packages) and it's working great for me.

I'll do this as a last resort but downloading 20MB+ is quite a big job
for my modem.

> You might want to search the web, deja (oops, it's gone),
> newsgroups, docs, etc, for any errata noted with your specific brand
> of sound card and modem.

I've searched news and the web already.  Today I found a message of
someone who seems to have had a similar problem.  I'll wait for his
answer before I'll waste even more time searching for the reason.

BTW I tried setting the kernel parameters `hda=slow hdb=slow'.  And
now the sound works flawlessly even when accessing a cd!  PPP still
doesn't work properly, though (At least _some_ packets come through
but still ~80% are lost).

Christoph