Alsa/Thinkpad/No such dsp device?

[warlord at MIT.EDU (Derek Atkins)]

Duane Morin <dmorin at morinfamily.com> writes:

> At 10:06 AM 5/10/2003 -0400, you wrote:
> >You've tried running aumix?
> 
> "error opening mixer".  More specifically, aumix by itself just
> returns me to the command line.  aumix -q tells me error opening mixer.

Hmm..  As I said, it worked fine for me on my 600.  I don't recall if
I had a 600E as well (I had two different 600 models, but sound
worked just fine on both of them).

>  >You clearly do not understand /proc...
> 
> And people wonder why everybody thinks Linux people are rude.  Obviously

Heh!  You think I'm rude, you should meet some friends of mine.... ;)
The problem is that people in general are lazy about looking up
information on their own -- they would rather ask a question and get
spoon-fed the answer than trying a simple google search and hoping to
learn on their own.  Perhaps I've spent too much time at MIT and have
a higher expectation of people, but I really don't want to start
thinking of everyone else as stupid.

> I don't understand it, you're right. But you'll note that I simply provided it
> as information, I didn't say "Wow, yeah, this must be it!"  Look at it
> from my side -- it's a directory, and *some* stuff in /proc you can
> cat, so I find
> it reasonable to presume that perhaps there is a file in there that should have
> something in it that doesn't.

As I said, /proc is magic.  You can cat files in /proc, but they have
no length because the "files" don't really exist.  They are all
ephemeral, generated by the kernel.  This is why it is "magic" :)

>  > crw-rw-rw-    1 root     root     116,  33 May 10 09:46 timer
> 
> 
> >These are not lengths; these are device numbers.  116,0; 116,24;
> >116,16; 116,33 Perfectly normal for a character device (see that 'c'
> >at the beginning of the line??)
> 
> Okey doke.  So I'm trying to learn -- does that mean that something /proc that
> does not have "x,y" where length should be must have not been assigned
> a device number?  Why are there two different numbers?  What exactly
> does it mean for the device number to be 0?

No, not really.

There are many different types of file nodes.  There are files (first
character is a -), there are directories ('d'), character devices
('c'), block devices ('b')...  Device nodes have no length; instead
they have a major/minor device number.  So, the 'timer' character
device above has a major number of 116, and a minor number of 33.
There is no length.  However, only devices have device numbers.  Files
and directories have lengths (although files in /proc usually just
have a length of zero).  Case in point:

--> ls -l /tmp/test.sh
-rw-rw-r--    1 warlord  mit           107 May  8 19:59 test.sh

This is a file (leads with a '-') of length 107.

--> ls -l /proc/uptime
-r--r--r--    1 root     root            0 May 10 11:02 uptime
--> cat /proc/uptime
1300094.45 1269083.55

As you can see, /proc is magic -- the file length is zero, but there
is real data in it.


Anyways, as much as I'd love to teach you more about /proc, it's
probably not going to help getting sound working on your TP.  Have you
tried looking at the linux-on-laptops pages and reading the multitude
of "linux on TP600" pages... Hopefully one of them will have the
information you need to get alsa running.  I seem to recall those
pages being pretty good when I used them a few years ago.

> Duane

-derek

-- 
       Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
       Member, MIT Student Information Processing Board  (SIPB)
       URL: http://web.mit.edu/warlord/    PP-ASEL-IA     N1NWH
       warlord at MIT.EDU                        PGP key available