Re: kernel command line parameter parsing is broken at drm_kms_helper.edid_firmwarewhen compiling under Fedora 18

From: Alex VillacÃÂs Lasso
Date: Mon Jan 21 2013 - 10:08:31 EST


El 19/01/13 20:21, Alex VillacÃs Lasso escribiÃ:
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".
BTW, I have CONFIG_DYNAMIC_DEBUG=y in my kernel config, and I tried adding dyndbg="file params.c +p" to the kernel command line, but I see no additional debug output that might point out what is happening.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/