[RFC] Loading of IDE modules by hw-detect

I've felt for a while that disk-detect is unnecessarily loading all available IDE modules. This may have been needed for 2.4 and was even useful to avoid some issues with the early SATA drivers, but hardware detection in the kernel has improved a lot since Sarge and Etch (ignoring for the moment the IDE->libata transition).

We're also being inconsistent as we only do this for IDE drivers and not for SCSI and SATA drivers. And finally it's totally ineffective as by the time the module selection dialog is being displayed, the drivers that are needed to actually support the hardware *have already been loaded automatically*.

Currently we load some 30 drivers by default, most of which remain unused as they are irrelevant for the system that's being installed. The attached (fairly simple) patch disables this and leaves things to the kernel/udev. It does support a boot parameter (hw-detect/load-ide=true) to force the old behavior.
The patch still leaves the (semi-)manual detection for modules for devices on Sparc sbus, HPPA bus and some others.

Patch has been tested for i386 (in VirtualBox) for both a netboot and CD-based install.

Results are:
- ~ 0.5MB memory saving

• speed up of the installation (loading all the drivers takes time...)
• less confusion for users who may wonder why seemingly random drivers are being selected
• shorter and more specific lsmod output

Some comments:
- one reason to list modules explicitly was to allow setting parameters for
them (especially ide-core); this is no longer really needed as module parameters can now also be passed at the boot prompt
- we also loaded the isofs module by default; this is not needed as it will
be loaded automatically if the '-t iso9660' option is used when mounting a CD (image), which we do in both cdrom-detect and iso-scan

The patch may well introduce regressions, probably mainly in arches other than i386/amd64. But I feel that we should start moving towards a less manual detection (as is done for the installed system) and the best time to do so is early in the release cycle.
We can easily add back targeted manual support where needed. I plan a call for testing if this change gets uploaded.

Cheers,
FJP

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