Bug 14164

Summary: "Unknown boot option" warning message should not be printed for options which will be passed to kernel modules
Product: Other Reporter: Adam Williamson (adamw)
Component: OtherAssignee: Rusty Russell (rusty)
Status: CLOSED CODE_FIX    
Severity: normal CC: alan, jcm, mishu, rdunlap, rusty
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: all Tree: Mainline
Regression: No

Description Adam Williamson 2009-09-11 16:28:54 UTC
When passing a kernel parameter of the type:

radeon.modeset=0

the kernel will throw a warning message that says "Unknown boot option 'radeon.modeset=0'. Ignoring..." However, the parameter is not ignored, it is passed to (and parsed by) the radeon module.

We (Fedora QA/BugZappers) find people are often confused or worried by this message when we ask them to use such a parameter, and worry that it is not being applied correctly. The kernel should not print this warning/error message when the parameter is of a format that will cause it to be passed to a kernel module.
Comment 1 Rusty Russell 2009-09-22 02:50:17 UTC
Is this because modern modprobe is scraping these options from /proc/cmdline?  If so, yes, we should suppress those messages altogether.

CC'd Jon, he'd know.
Comment 2 Adam Williamson 2009-09-22 04:51:52 UTC
I don't know how it's implemented, exactly, that may well be how it works. I just know that you can pass any module parameter as a kernel command line parameter in that format (modulename.moduleparameter=value) and it gets passed on somehow.
Comment 3 Adam Williamson 2009-11-26 17:43:30 UTC
ping? this still regularly causes confusion for users when we're trying to debug various issues, see https://bugzilla.redhat.com/show_bug.cgi?id=538840#c3 for a recent example: it's a 'cosmetic' bug but with unfortunate effects.
Comment 4 Jon Masters 2010-03-21 12:03:01 UTC
Yea, exactly that's what happens. Modprobe pulls out those arguments and processes them.

I don't know why I missed this bug, but that should be fixed now. I even have daily reminders setup and should get CC'd on every module issue from now on.