On my laptop, a Dell E7270, I boot OpenSuse 42.3 from a USB pen drive and the system works well but one thing: the suspend/resume does not work if the power cord is not plugged. Below what I can see when I try to resume from the suspended state.
62.337226] usb2-port3: cannot disable (err = -32)
62.396010] Buffer I/O error on device sdb3, logical block 13329480
62.392391] Aborting Journal on device sdb3-0.
62.392810] JBD2: Error -5 detected when updating Journal superblock for sdb3-0.
62.397061] EXT4-fs error (device sdb3): ext4_journal_check_start:61: Detected aborted journal
62.397916] EXT4-fs (sdb3): Remounting filesyetem read-only
62.397952] EXT4-fs (sdb3): previous I/O error to superblock detected
62.398119] systemd-journald: Failed to truncate file to its own size Read-only file system
62.436216] EXT4-fs error (device sdb3): ext4-find-entry :1436: inode #263057: comm systemd: reading directory lblock 0
62.455498] EXT4-fs error (device sdb3): ext4-find-entry :1436: inode #263057: comm kworker/u0:26: reading directory lblock 0
67.420156] systemd-journald: Failed to truncate file to its own size: Read-only file system
I found only a post on the Internet should give the solution but it requires to modify the kernel - I do not want to do.
Any simpler solution that update/compile the kernel?
Why should the filesystem be read-only? It is a full installation on the pen drive.
The problem should be: when the power cord is unplugged the laptop remove the power to the USB and when it resumes the drive is still off. The kernel modification introduce a delay at resume to let the drive to wake up and find it ready.
If power is removed from the USB devices when mains power is lost, then the resume does not matter. The problem is there is no suspend because there was not enough time for the RAM image to be written to the powered-off USB device.
There can be no kernel timing problem on resume because the USB boot process cannot start before power is restored. The read-only state was induced by a bad superblock on an Ext4 file-system (so not the swap partition used for suspend-resume data) which might or might not be repairable by fsck while unmounted. The damage might well be related to power loss during a critical write operation.
If power is removed from the USB devices on mains power loss, then there is a power management problem. Check Power Management in System /settings and the Dell Bios. Is your battery OK?