How do I disable edid check on kernel command line?

Flash flashl at
Wed Jul 2 13:12:33 UTC 2014

Thanks for reply. Finally realized why I couldn't locate EDID folder, 
kernel docs weren't installed.
Built default edids, copied 1920x1080.bin to /lib/firmware and 
/lib/firmware/edid, adds 
drm_kms_helper.edid_firmware=DVI-I-1:edid/1920x1080.bin drm_debug=14 
log_buf_len=16M to commandline. No change in behavior, commandline 
firmware helper ignored. Boot DVI-I-1 signal drops during and/or after 
LUKS prompt. Next, invalid EDID message appears although 
/usr/bin/edid-decode validates /lib/firmware/1920x1080.bin.

My guesstimation so far is (1) once DVI-I-1 signal drops during boot 
nothing I've done so far 're-connects' DVI-I-1; (2) although 
1920x1080.bin is placed in /lib/firmware and /lib/firmware/edid neither 
is found yet there is no notification/complaint; (3) for whatever 
reason, video:DVI-I-1:e is also ignored. Is there another commandline 
option to keep signal on for DVI-I-1?

Thanks again

On 2014-07-01 15:41, poma wrote:
> On 01.07.2014 18:50, flashl at wrote:
>> Current Kernel is 3.14.9-200 x86_64. This is a multihead setup; i915 
>> and
>> NV96 video cards (displays HMDI2 = i915 and NV96 DVI-I-1 and VGA-2 
>> [both
>> X233H Acer]). kernel bootmenu is presented from DVI-I-1, after kernel
>> selection, LUKS prompt appears on HMDI2 and DVI-I-1 is disconnected. 
>> In
>> multi-user env HDMI2 and VGA-2 are active and dmesg shows edid 
>> complaint
>> about DVI-I-1. /usr/bin/edid-decode complains about edid block for 
>> both
>> NV96 displays DVI and VGA but for whatever reason DVI is only one
>> disconnected.
>> So far searches in various forum threads and bugzilla suggest buggy 
>> DVI
>> edid problems been around for awhile. The DVI edid block error follows
>> DVI connector, meaning, moving DVI cable to monitor previously with
>> label VGA-2 will produce same edid message. I haven't found complete
>> instructions to build CustomEdid yet, that seems the way to go since
>> commandline settings like drm_edid_strict, video=DVI-I-1:e are 
>> ignored.
>> Pointers to documentation to build customedid or kernel commandline to
>> disable DVI edid checking will be greatly appreciated.
>> Thanks in advance.
> drm_kms_helper.edid_firmware=[<connector>:]<file>
> 	Broken monitors, graphic adapters and KVMs may
> 	send no or incorrect EDID data sets. This parameter
> 	allows to specify an EDID data set in the
> 	/lib/firmware directory that is used instead.
> 	Generic built-in EDID data sets are used, if one of
> 	edid/1024x768.bin, edid/1280x1024.bin,
> 	edid/1680x1050.bin, or edid/1920x1080.bin is given
> 	and no file with the same name exists. Details and
> 	instructions how to build your own EDID data are
> 	available in Documentation/EDID/HOWTO.txt. An EDID
> 	data set will only be used for a particular connector,
> 	if its name and a colon are prepended to the EDID
> 	name.
> poma

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