Ubuntu

System goes to emergency mode at every boot time. FIFO underrun error.

Asked by OccamsRazor

My laptop is installed with only ubuntu 16.04. In recent times whenever I want to start the machine normally, it goes to a state stating "Welcome to emergency mode". The previous two lines state some FIFO underrun error on PCH transcoder A.

journalctl -xb gives the following errors:

[drm: intel_set_pch_fifo_underrun_ reporting [i915]] *ERROR* uncleared pch fifo underrun on pch transcodcer A.
[drm: intel_pch_fifo_underrun_irq_handler [i915]]

fsck failed with error code 4.

Failed to start file system check on /dev/disk/by-uuid/...

Dependency failed for home.

The only way I can start the machine is going to recovery mode. Then performing fsck once and then resuming. I have to do this every time I want to start up.

How to come out of this error?

[The emergency mode screen asks to have a ^D to start normally. But it goes to ubuntu startup screen once, and then again comes to emergency mode screen.]

Question information

Language:
English Edit question
Status:
Solved
For:
Ubuntu Edit question
Assignee:
No assignee Edit question
Solved by:
Manfred Hampl
Solved:
Last query:
Last reply:
Revision history for this message
actionparsnip (andrew-woodhead666) said : 		#1

Have you tested your RAM using Memtest86 from GRUB?
Have you tried testing the drive using the manufacturer's tool? (You can get this on the Ultimate Boot CD for the big hitters here)

Revision history for this message
OccamsRazor (arijitshaw95) said : 		#2

Memtest showed no error. Dell's Enhanced Pre-boot System Assessment (ePSA) Diagnostics also passed successfully.

Revision history for this message
OccamsRazor (arijitshaw95) said : 		#3

Some reported this as a bug. like here*. Am I really stuck in a bug that was reported in 2012?

* https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1451632

Revision history for this message
Manfred Hampl (m-hampl) said : 		#4

I assume that you are facing two different problems:

1. the "fifo underrun" is related to display
2. the "fsck failure" is related to hard disk

I suggest that you boot a live system (from an Ubuntu installation DVD or bootable USB stick in the "Try Ubuntu without installing" mode) and perform a full file system check on your hard disk partitions.

You should also verify that the disk uuids as shown by the blkid command match with the ones in your /etc/fstab file.

Revision history for this message
OccamsRazor (arijitshaw95) said : 		#5

fstab has an error

# / was on /dev/sda2 during installation
UUID=b49db6b0-37d4-4088-ac3c-cdb8f94fb9a0 / ext4 errors=remount-ro 0 1

 can it be a reason for that?

i think, fsck is the main problem rather than fifo underrun.

Revision history for this message
Best Manfred Hampl (m-hampl) said : 		#6

RE: "fstab has an error":
Which error do you see with your fstab file?

And yes that is what I wanted to say:
The fifo underrun error should not prevent booting, but might cause some screen flickering or other display errors.
The more critical messages is the failure of fsck.

Return code 4 of fsck means "Filesystem errors left uncorrected".
I assume that the only solution to this is booting a live system and running a full file system check, which hopefully will be able to correct the filesystem errors.

Revision history for this message
OccamsRazor (arijitshaw95) said : 		#7

Thank you m-hampl. Booting a live system and running fsck solved the problem. There was a problem on /dev/sda2.

Revision history for this message
OccamsRazor (arijitshaw95) said : 		#8

Thanks Manfred Hampl, that solved my question.