Bug 3487

> Thanks for the info.  I still think it's a bandaid though: the real problem
> is that the logic in the init script is broken.  Anything that causes modules
> to be loaded before the init script is run breaks the script, as far as I can
> see.  For example: compiling into the kernel, i.e. not as modules ; using
> hardware detection software that autoloads sound card drivers ; using usb
> audio...  In these cases /proc/asound will exist when the init script is run,
> and mixer settings will not be restored, card specific scripts will not be run
etc.
> 
> In the long term (2.6 kernel) I am imagining the following:
> 
> (1) the init script just loads modules.
> (2) when modules are loaded, whether for a pci card, a usb one whatever,
> the hotplug subsystem is called: it restores mixer settings for the card and
> runs card specific scripts.

except for the check of /proc/asound, the hotplug problem can be
sorted to the following:

1. hotplug may be called before alsa init script.

2. hotplug needs to manage the mixer configuration of plugged /
   unplugged devices dynamically.

3. alsa initscript itself should be independent from hotplug.

they are not all but certainly a major part of the problems.


the first one is not easy, because the network devices can belong to
hotplug, too.  the scenario is like this:
  many alsa files are located under /usr
    -> a networkfs (e.g. NFS) is required before the alsa service
      -> the network must be initialized in prior
        -> the network base = hotplug is needed to run before alsa!

the second problem is also tough.
alsa driver needs to access the device to get the current mixer
values, but at the remove callback of hotplug, the device was actually
unplugged...  probably implementing cache would be necessary.

the third one is obvious.
i don't think it's good to let hotplug initialize the pci cards, too.
for example, if i don't have any usb devices, i'd like to remove
hotplug.  but if alsa initscript rely on the hotplug stuff, i cannot
do that.  that's bad.

well, still many obstacles ahead.
i'd love to see a perfect solution :)


Takashi