Re: For those who have no sound in their 32bit chroot

[Goswin von Brederlow <brederlo@informatik.uni-tuebingen.de>]

Matthias Julius <lists@julius-net.net> writes:

> "Gudjon I. Gudjonsson" <gudjon@mc2.chalmers.se> writes:
>
>> Hi Goswin and all the others
>>> >
>>> > # ia32 chroot
>>> > /home           /var/chroot/sid-ia32/home none  bind            0       0
>>> > /tmp            /var/chroot/sid-ia32/tmp none   bind            0       0
>>> > proc            /var/chroot/sid-ia32/proc proc  defaults        0       0
>>> > /dev            /var/chroot/sid-ia32/dev none   bind            0       0
>>> >
>>> > Well obviously there's more to it, this is just the relevant part ;)
>>> >
>>> > I hope this can help somebody.
>>> > I have sound in flash and mplayer with no other configuration required:
>>> > please note I use esd in my gnome desktop, not sure if it's relevant or
>>> > not.
>>> >
>>> > Enjoy!
>>>
>>> You are missing /sys and /dev/pts.
>>>
>>> MfG
>>>         Goswin
>> Now there is one thing I don't understand. I do have sound with the following 
>> entries in fstab (thanks to a hint from Lennart)
>> # ia32 chroot
>> /home           /var/chroot/sid-ia32/home none  bind            0       0
>> /tmp            /var/chroot/sid-ia32/tmp none   bind            0       0
>> /dev            /var/chroot/sid-ia32/dev none   rbind           0       0
>> proc            /var/chroot/sid-ia32/proc proc  defaults        0       0
>> rbind makes a difference
>
> Yes, with rbind you don't need to mount /dev/pts separately

Except that the mtab will not reflect the mounted filesystems then
iirc and umounting might fail. Better to list the sub-mounts
specifically.

>> but I have no no mounting to /sys, perhaps I should add that but according to 
>> the debian reference manual it should be done in another way. 
>
> /sys shouldn't be needed for sound.  But, for other hardware like USB
> scanners it might be necessary.
>
>> http://www.debian.org/doc/manuals/reference/ch-tips.en.html#s-chroot
>> chroot # cd /dev; /sbin/MAKEDEV generic; cd -
>
> I wouldn't create a static /dev in a chroot on a system that uses udev.

Unless it is a buildd chroot or something where you do want a minimal
/dev. But for a user chroot having it reflect the system is better.

>>    Is this difference documented somewhere or can you explain this? It might 
>> explain why my 32 bit xoscope cannot access the 64 bit comedi lib driver.

Generally 32bit and 64bit can't be mixed in the same address
space. You can't dlopen a 64bit lib in a 32bit application for
example.

> I have no clue about this :)
>
> What is xoscope and comedi?
>
> Matthias

MfG
        Goswin