Comment 272 for bug 1776563

siyia, you have exactly the same laptop model as I have, they should work. You do something wrong. Maybe you use an incorrect grub or kernel parameter.

this a section of my /boot/grub/grub.cfg. Yours should look like this.
### BEGIN /etc/grub.d/40_custom_proxy ###
menuentry "Ubuntu" --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-0986d268-5f46-4555-9214-1d9dffa79286' {
 recordfail
 load_video
 gfxmode $linux_gfx_mode
 insmod gzio
 if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
 insmod part_gpt
 insmod ext2
 set root='hd0,gpt2'
   acpi /boot/amls/ssdt10.aml
   acpi /boot/amls/ssdt11.aml
   acpi /boot/amls/ssdt13.aml
   acpi /boot/amls/ssdt14.aml
   acpi /boot/amls/ssdt1.aml
   acpi /boot/amls/ssdt2.aml
   acpi /boot/amls/ssdt3.aml
   acpi /boot/amls/ssdt4.aml
   acpi /boot/amls/ssdt5.aml
   acpi /boot/amls/ssdt6.aml
   acpi /boot/amls/ssdt8.aml
   acpi /boot/amls/ssdt9.aml
 if [ x$feature_platform_search_hint = xy ]; then
   search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt2 --hint-efi=hd0,gpt2 --hint-baremetal=ahci0,gpt2 0986d268-5f46-4555-9214-1d9dffa79286
 else
   search --no-floppy --fs-uuid --set=root 0986d268-5f46-4555-9214-1d9dffa79286
 fi
 linux /boot/vmlinuz-4.18.0-10-generic root=UUID=0986d268-5f46-4555-9214-1d9dffa79286 ro ivrs_ioapic[4]=00:14.0 ivrs_ioapic[5]=0:00.2 quiet splash $vt_handoff
 initrd /boot/initrd.img-4.18.0-10-generic

Additional kernel parameters aren't needed. Don't change iommu settings or anything else. Iommu should be enabled in bios menu.