I installed today Ubuntu 18.04. I have a secondary monitor (Acer AL1914), which does not provide a EDID, so I created one and usually loaded directly from the kernel at startup.
The EDID is located here:
/lib/firmware/edid/al1914.bin
The kernel command line is this:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash drm_kms_helper.edid_firmware=VGA-1:edid/al1914.bin"
On Ubuntu 16.04, this worked perfectly. Now, the additional mode from the edid is not present among the resolutions available (I have to create a new one and add it with cvt and xrandr once the system is loaded).
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: xorg 1:7.7+19ubuntu6
ProcVersionSignature: Ubuntu 4.15.0-13.14-generic 4.15.10
Uname: Linux 4.15.0-13-generic x86_64
ApportVersion: 2.20.9-0ubuntu4
Architecture: amd64
BootLog: Error: [Errno 13] Permesso negato: '/var/log/boot.log'
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Sun Apr 8 08:27:19 2018
DistUpgraded: Fresh install
DistroCodename: bionic
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes
GraphicsCard:
Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09) (prog-if 00 [VGA controller])
Subsystem: Samsung Electronics Co Ltd 3rd Gen Core processor Graphics Controller [144d:c0d8]
Advanced Micro Devices, Inc. [AMD/ATI] Thames [Radeon HD 7500M/7600M Series] [1002:6840] (rev ff) (prog-if ff)
InstallationDate: Installed on 2018-04-07 (0 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Beta amd64 (20180404)
MachineType: SAMSUNG ELECTRONICS CO., LTD. 350V5C/351V5C/3540VC/3440VC
ProcEnviron:
TERM=xterm-256color
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=it_IT.UTF-8
SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-13-generic.efi.signed root=UUID=088e46ca-c64d-43c6-8c68-0f92cb2917b6 ro quiet splash drm_kms_helper.edid_firmware=VGA-1:edid/al1914.bin vt.handoff=1
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/04/2013
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: P09ABE
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: NP350V5C-S08IT
dmi.board.vendor: SAMSUNG ELECTRONICS CO., LTD.
dmi.board.version: BOARD REVISION 00
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 9
dmi.chassis.vendor: SAMSUNG ELECTRONICS CO., LTD.
dmi.chassis.version: 0.1
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrP09ABE:bd07/04/2013:svnSAMSUNGELECTRONICSCO.,LTD.:pn350V5C/351V5C/3540VC/3440VC:pvrP09ABE.012.CP:rvnSAMSUNGELECTRONICSCO.,LTD.:rnNP350V5C-S08IT:rvrBOARDREVISION00:cvnSAMSUNGELECTRONICSCO.,LTD.:ct9:cvr0.1:
dmi.product.family: Eureka
dmi.product.name: 350V5C/351V5C/3540VC/3440VC
dmi.product.version: P09ABE.012.CP
dmi.sys.vendor: SAMSUNG ELECTRONICS CO., LTD.
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.91-2
version.libgl1-mesa-dri: libgl1-mesa-dri 18.0.0~rc5-1ubuntu1
version.libgl1-mesa-glx: libgl1-mesa-glx 18.0.0~rc5-1ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.19.6-1ubuntu3
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:18.0.1-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20171229-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.15-2
Status changed to 'Confirmed' because the bug affects multiple users.