kern/49836: Circular module dependency

[paul%whooppee.com@localhost]

>Number:         49836
>Category:       kern
>Synopsis:       circular module dependency
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Apr 12 22:40:00 +0000 2015
>Originator:     Paul Goyette
>Release:        NetBSD 7.99.9
>Organization:
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| Paul Goyette     | PGP Key fingerprint:     | E-mail addresses:       |
| (Retired)        | FA29 0E3B 35AF E8AE 6651 | paul at whooppee.com    |
| Network Engineer | 0786 F758 55DE 53BA 7731 | pgoyette at juniper.net |
| Kernel Developer |                          | pgoyette at netbsd.org  |
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>Environment:
System: NetBSD pokey.whooppee.com 7.99.9 NetBSD 7.99.9 (POKEY 2015-04-09 09:49:29) #0: Sat Apr 11 14:57:21 PHT 2015 paul%pokey.whooppee.com@localhost:/build/netbsd-local/obj/amd64/sys/arch/amd64/compile/POKEY amd64
Architecture: x86_64
Machine: amd64
>Description:
	Module 'hdaudio' references symbol hdaudio_cd, which is defined 
	in module 'hdaudio_pci'.  However, module 'hdaudio_pci' has an
	explicit dependency on module 'hdaudio'.  Neither of these two
	modules can be loaded because requires the other.
>How-To-Repeat:
	Build a kernel without any audio or hdaudio stuff.  Build the
	corresponding mdoules.  Then, try to "modload hdaudio" and it
	will complain "linker error: symbol `hdaudio_cd' not found".

	The required symbol is defined in module hdaudo_pci, so try to
	'modload hdaudio_pci'.  It attempts to load 'hdaudio' because of  
	the explicit dependancy, and 'hdaudio' fails as above.
>Fix:
	Unknown.  But the various audio and hdaudio modules (and the
	corresponding {,hd}audiobus stuff) seems to need a significant 
	overhaul.  See following comments:

	http://mail-index.netbsd.org/current-users/2015/04/09/msg027084.html

>Unformatted: