linux-kernel - kernel command line parameter parsing is broken at drm_kms_helper.edid

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Message-ID: <50FB4697.1050907@palosanto.com>
Date:	Sat, 19 Jan 2013 20:21:27 -0500
From:	Alex Villacís Lasso <a_villacis@...osanto.com>
To:	linux-kernel@...r.kernel.org
Subject: kernel command line parameter parsing is broken at drm_kms_helper.edid_firmware
 when compiling under Fedora 18

I am having this strange issue. My computer has a LCD display that does 
not send any EDID, and therefore I need the command parameter 
"drm_kms_helper.edid_firmware=edid/1280x1024.bin" In Fedora 16, the 
stock kernel does not have CONFIG_DRM_LOAD_EDID_FIRMWARE set. Therefore 
I compiled my own kernel from vanilla sources, and the parameter worked. 
I have just now upgraded to Fedora 18. The new stock kernel is supposed 
to have CONFIG_DRM_LOAD_EDID_FIRMWARE set, but when I boot with the 
drm_kms_helper parameter, I get a message "drm_kms_helper: Unknown 
parameter `bin'". I thought this was a kernel bug caused by some patch 
in the stock kernel, so I filed 
https://bugzilla.redhat.com/show_bug.cgi?id=901899 , and then proceeded 
to compile 3.8-rc4 from vanilla sources. However, I am surprised to find 
that the vanilla sources, when compiled under Fedora 18, exhibit the 
same bug. Has anyone seen a situation like this? Is this a possible 
compiler bug in Fedora 18? A grub2 bug? Apparently the kernel is 
misparsing the commandline parameter and thinks "bin" is the module 
parameter, not "edid_firmware".

View attachment "dmesg.txt" of type "text/plain" (56347 bytes)