Bug 470143

Summary:	mac80211 built-in, causing mysterious errors with compat-wireless
Product:	[Fedora] Fedora	Reporter:	Hin-Tak Leung <htl10>
Component:	kernel	Assignee:	John W. Linville <linville>
Status:	CLOSED RAWHIDE	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	rawhide	CC:	1159062847, kernel-maint, mcgrof, quintela
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Hardware:	All
OS:	Linux
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Fixed In Version:		Doc Type:	Bug Fix
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Last Closed:	2008-11-11 16:19:03 UTC	Type:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Embargoed:

Description Hin-Tak Leung 2008-11-05 22:16:48 UTC

Description of problem:
compat-wireless (http://linuxwireless.org/en/users/Download) a way of using the latest wireless stack without building a whole new kernel, by replacing 
the whole of wireless stack - which is a bit smaller and easier/quicker to
replace. Sometimes wireless-testing/compat-wireless needs to change mac80211, and this is impossible with fc10 kernels, because mac80211 is compiled-in.

Version-Release number of selected component (if applicable):
kernel-2.6.27.4-79.fc10.x86_64

How reproducible:
Always

Steps to Reproduce:
1. build compat-wireless,
2. make install, make unload, make load
3. mysterious errors or even kernel oops happens.
  
Actual results:
mysterious errors or even kernel oops happens.

Expected results:
The wireless stack + drivers replaced by compat-wireless and have operational wireless networking

Additional info:
fc9 kernels (e.g. kernel-2.6.27.4-24.fc9.x86_64) have mac80211 as a kernel module.

Probably should assign this to John Linville :-).

Comment 1 Hin-Tak Leung 2008-11-05 23:15:19 UTC

I looked through koji and found it was removed between 
0.345.rc7.fc10
0.339.rc7.fc10
but the log entry between does not say why.

Comment 2 John W. Linville 2008-11-06 14:08:04 UTC

I advised against it for exactly this reason.  The notion was that this would save time during boot and that anyone who could build compat-wireless could just build their own kernel anyway...whatever.  I think it was the wrong decision.

Comment 3 Dave Jones 2008-11-06 16:05:56 UTC

lets move it back to modular then.  There's always going to be trade-offs, and I think in this case, the benefits of a marginally slower boot are outweighed by the improved debugging you get.

Comment 4 Hin-Tak Leung 2008-11-06 17:58:20 UTC

compat-wireless is considerably easier and quicker to build; particularly in the situation where one wants to try out new changes (and easily revertable, just by
blowing away /lib/module/<version>/updates and then depmod -a), without whole-sale dev kernel. As for slower boot, it is probably marginal compared to per-driver initialization - and some might argue in the opposite - not all machines have wireless cards.

Comment 5 Hin-Tak Leung 2008-11-09 03:46:37 UTC

2.6.27.5-88.fc10.x86_64 just available on koji has the mac80211 component 
as module.

change log:

* Wed Nov 05 2008 John W. Linville <linville> 2.6.27.4-83
- Re-modularize mac80211 component (#470143)

Thank you!