Re: Loading therm_* modules in d-i on Macs

[Sven Luther <sven.luther@wanadoo.fr>]

On Wed, Jun 30, 2004 at 01:40:52AM +0100, Colin Watson wrote:
> It'd be rather nice if the new debian-installer could load the
> therm_adt746x or therm_windtunnel modules, and register them so that
> they're automatically loaded by the installed system.
> 
> I can take care of the d-i implementation, but what's the best way to
> decide whether the modules are required? As I see it, there are two
> obvious methods:
> 
>   (1) Probe each module unconditionally on powerpc/powermac_newworld,
>       and register it in /etc/modules if modprobe exited 0. The modules
>       in question check for the required hardware themselves and exit
>       -ENODEV if they don't find it.
> 
>     Pros: simple; should be effective.
> 
>     Cons: brute-force approach; generates spurious errors which will
>     probably have to be logged just in case anything real goes wrong;
>     won't register the module if it's needed by the hardware but the
>     probe failed for some installer-specific reason.
> 
>   (2) Take the logic from the respective module *_init functions,
>       reimplement it in shell by poking about in /proc/device-tree (I've
>       looked at the kernel code and believe this is straightforward),
>       and probe and register whatever that says will work.
> 
>     Pros: accurate about what should go in /etc/modules, regardless of
>     glitches in the installer environment; no spurious errors, only real
>     ones.
> 
>     Cons: code duplication, so would have to stay in sync with the
>     kernel (although d-i's kernels won't rev very often once we go
>     stable); more complex.
> 
> Do any kernel hackers have an opinion here?

I would go for the second method, since there is less chance of breaking
stuff, it is more elegant, and probably also faster. Not sure i qualify
as a kernel hacker though.

Friendly,

Sven Luther