Hi!
I upgraded to new kernel 5.0.0-21 in 19.04.
Systemd shows me on boot 'i2c errors':
kernel: [ 14.509890] i2c i2c-2: SMBus Timeout!
kernel: [ 14.509952] i2c i2c-2: Failed reset at end of transaction (01)
kernel: [ 14.510064] i2c i2c-2: Failed! (01)
How to fix these errors on boot?
kernel: [ 16.686234] i2c i2c-2: SMBus Timeout!
kernel: [ 16.686296] i2c i2c-2: Failed reset at end of transaction (01)
kernel: [ 16.686438] i2c i2c-2: Failed! (01)
kernel: [ 16.686516] i2c i2c-2: Failed! (01)
anyone can help?
I blacklisted a few modules about "sensors"...
blacklist adt7475
blacklist hwmon_vid
blacklist i2c_piix4
blacklist it87
blacklist k10temp
Now the i2c-2 errors are gone on boot but a new error appears on boot:
kernel: [ 3614.068109] db_root: cannot open: /etc/target
I found the solution for my problem 
Upgraded to kernel 5.0.0-23-generic
Still blacklisted: "/etc/modprobe.d/sensors"
(sensors is the file that I have created before a few days ago)
blacklist adt7475
blacklist hwmon_vid
blacklist it87
blacklist k10temp
Removed from blacklist: "/etc/modprobe.d/sensors"
blacklist i2c_piix4
Removed from: "/etc/initramfs-tools/modules"
vhost_scsi
sudo update-initramfs -u
Added to the GRUB_CMDLINE_LINUX_DEFAULT
in "/etc/default/grub"
GRUB_CMDLINE_LINUX_DEFAULT="initcall_blacklist=i2c_dw_init_master"
then:
sudo update-grub
...now, the i2c-2 errors and db_root: cannot open: /etc/target
problem are gone.