This issue appears to be an upstream bug, since you tested the latest upstream kernel. Would it be possible for you to open an upstream bug report[0]? That will allow the upstream Developers to examine the issue, and may provide a quicker resolution to the bug.
Please follow the instructions on the wiki page[0]. The first step is to email the appropriate mailing list. If no response is received, then a bug may be opened on bugzilla.kernel.org. Once this bug is reported upstream, please add the tag: 'kernel-bug- reported-upstream'. [0] https://wiki.ubuntu.com/Bugs/Upstream/kernel ** Changed in: linux (Ubuntu) Status: Confirmed => Triaged -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1574178 Title: 4.4.0-21 "gave up waiting for root device" Status in linux package in Ubuntu: Triaged Bug description: On a Lenovo A740, after upgrading to Xenial I have to downgrade to kernel 4.2.0-35 in order to be able to boot at all. My current /etc/default/grub: # If you change this file, run 'update-grub' afterwards to update # /boot/grub/grub.cfg. # For full documentation of the options in this file, see: # info -f grub -n 'Simple configuration' #GRUB_DEFAULT=0 #KBU: 4.4.0 doesn't find root :((( GRUB_DEFAULT="Advanced options for Ubuntu>Ubuntu, with Linux 4.2.0-35-generic" #GRUB_HIDDEN_TIMEOUT=0 GRUB_HIDDEN_TIMEOUT_QUIET=true GRUB_TIMEOUT=5 GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian` #GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" GRUB_CMDLINE_LINUX_DEFAULT="" GRUB_CMDLINE_LINUX="noprompt persistent" # Uncomment to enable BadRAM filtering, modify to suit your needs # This works with Linux (no patch required) and with any kernel that obtains # the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...) #GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef" # Uncomment to disable graphical terminal (grub-pc only) #GRUB_TERMINAL=console # The resolution used on graphical terminal # note that you can use only modes which your graphic card supports via VBE # you can see them in real GRUB with the command `vbeinfo' #GRUB_GFXMODE=640x480 # Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux #GRUB_DISABLE_LINUX_UUID=true # Uncomment to disable generation of recovery mode menu entries #GRUB_DISABLE_RECOVERY="true" # Uncomment to get a beep at grub start #GRUB_INIT_TUNE="480 440 1" This is the same system as https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1463422 See attached image for what the screen looks like when trying to boot 4.4. My USB keyboard also stops working there so I can't actually type anything into the busybox. --- ApportVersion: 2.20.1-0ubuntu2 Architecture: amd64 AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/hwC0D0', '/dev/snd/pcmC0D8p', '/dev/snd/pcmC0D7p', '/dev/snd/pcmC0D3p', '/dev/snd/controlC0', '/dev/snd/hwC1D0', '/dev/snd/by-path', '/dev/snd/pcmC1D0c', '/dev/snd/pcmC1D0p', '/dev/snd/controlC1', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1: DistroRelease: Ubuntu 16.04 HibernationDevice: RESUME=UUID=dc4226ca-3ebe-4611-95ac-c1a0ccbb7d7a InstallationDate: Installed on 2015-06-04 (325 days ago) InstallationMedia: Xubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422.1) MachineType: LENOVO F0AM Package: linux (not installed) ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.2.0-35-generic.efi.signed root=UUID=91533e8a-b5ca-4447-8c4a-b5bb2d095238 ro noprompt persistent ProcVersionSignature: Ubuntu 4.2.0-35.40-generic 4.2.8-ckt5 PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon. RelatedPackageVersions: linux-restricted-modules-4.2.0-35-generic N/A linux-backports-modules-4.2.0-35-generic N/A linux-firmware 1.157 RfKill: Tags: xenial xenial Uname: Linux 4.2.0-35-generic x86_64 UnreportableReason: The report belongs to a package that is not installed. UpgradeStatus: Upgraded to xenial on 2016-04-23 (1 days ago) UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo _MarkForUpload: False dmi.bios.date: 09/30/2014 dmi.bios.vendor: LENOVO dmi.bios.version: O00KT19AUS dmi.board.name: INVALID dmi.board.vendor: LENOVO dmi.board.version: 31900058 STD dmi.chassis.type: 13 dmi.chassis.vendor: LENOVO dmi.chassis.version: Chassis Version dmi.modalias: dmi:bvnLENOVO:bvrO00KT19AUS:bd09/30/2014:svnLENOVO:pnF0AM:pvrLenovoA740:rvnLENOVO:rnINVALID:rvr31900058STD:cvnLENOVO:ct13:cvrChassisVersion: dmi.product.name: F0AM dmi.product.version: Lenovo A740 dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1574178/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
