Why are cardbus drivers cbb(4) and pccard(4) still included in GENERIC?

Warner Losh imp at bsdimp.com
Thu Aug 29 15:50:22 UTC 2013


On Aug 29, 2013, at 8:54 AM, John Baldwin wrote:

> On Thursday, August 29, 2013 6:56:53 am Adrian Chadd wrote:
>> Hm! Are they dynamically loaded if you insert the cards?
>> 
>> (Ie, has devd been taught about them as appropriate?)
> 
> These are drivers for the bridges, not for cards you plug into the bridges.  
> If you autoloaded them at all you would load them during boot when you saw an 
> appropriate PCI device.  Currently we don't autoload any PCI drivers, so I 
> don't think that should be a blocker for taking these out of GENERIC.
> 
> Warner is probably the best person to ask.

We don't autoload them. The bridge code is tiny and can easily be removed if you want to create a custom kernel.  There's still plenty of laptops that would be crippled if these were removed. Other drivers that are even more obsolete that are still in GENERIC:
	esp
	sym
	trm
	adv
	adw
	aic
	bt
	asr
	ciss
	iir
	ida
	de
	cas
	dc
	gem
	hme
	nfe
	nve
	pcn (although many VM env like this)
	rl
	fs
	sis
	tl
	tx
	vr
	wb
	xl
	cs
	ed
	ex
	ep
	fe
	sn
	xe
	an
	wi
	urio
	uipaq
	aue
	cue
	kue
	rue

So asking why cbb and cardbus are still there seems a little silly to me.

The basic problem is that our PCI and USB infrastructure doesn't include the basic information necessarily to properly look at a directory of .ko files and know what to autoload when it finds an unmatched device. PC Card could easily do this, but doesn't (I have some doodles from a few years ago that would put this stuff into an elf section that could (a) be unloaded after probe (optionally) and (b) be read by automatic tools to load just what's needed). USB is a lot closer than PCI, which is why Hans' scripts work well enough to create uber-ugly devd config files.

Rather than shooting randomly, perhaps some investigation about this topic would be in order. We've talked it to death, but nobody has had the time to STFU and implement something reasonable.

Warner


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