boot screen give this

[ibrahim]

drm:cpt_set_fifo_underrun_reporting] ERROR uncleared pch fifo underrun on pch transcoder A [drm:cpt_serr_int_handler] ERROR PCH transcoder A FIFO underrun

during startup it gives this error and continue working . i can use ubuntu but whats the reason behind this error ?

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: xorg 1:7.7+13ubuntu3
ProcVersionSignature: Ubuntu 4.4.0-38.57-generic 4.4.19
Uname: Linux 4.4.0-38-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_modeset nvidia wl
.proc.driver.nvidia.gpus.0000.01.00.0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/gpus/0000:01:00.0'
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86_64 Kernel Module 361.42 Tue Mar 22 18:10:58 PDT 2016
 GCC version: gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.2)
.tmp.unity_support_test.0:

ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CurrentDesktop: Unity
Date: Fri Oct 14 17:11:27 2016
DistUpgraded: Fresh install
DistroCodename: xenial
DistroVariant: ubuntu
GraphicsCard:
 Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Lenovo 3rd Gen Core processor Graphics Controller [17aa:3902]
 NVIDIA Corporation GF108M [GeForce GT 635M] [10de:0de3] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: Lenovo GF108M [GeForce GT 635M] [17aa:3902]
InstallationDate: Installed on 2016-10-07 (6 days ago)
InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
MachineType: LENOVO IdeaPad Z580
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-38-generic root=UUID=fc2fc1f1-7700-4c16-b83d-ed23d95063a2 ro quiet splash
SourcePackage: xorg
Symptom: display
Title: Xorg freeze
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 09/20/2012
dmi.bios.vendor: Phoenix Technologies Ltd.
dmi.bios.version: 5FCN91WW
dmi.board.asset.tag: No Asset Tag
dmi.board.name: Lenovo
dmi.board.vendor: LENOVO
dmi.board.version: 31900004WIN8 STD SGL
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Lenovo Z580
dmi.modalias: dmi:bvnPhoenixTechnologiesLtd.:bvr5FCN91WW:bd09/20/2012:svnLENOVO:pnIdeaPadZ580:pvrLenovoZ580:rvnLENOVO:rnLenovo:rvr31900004WIN8STDSGL:cvnLENOVO:ct10:cvrLenovoZ580:
dmi.product.name: IdeaPad Z580
dmi.product.version: Lenovo Z580
dmi.sys.vendor: LENOVO
version.compiz: compiz 1:0.9.12.2+16.04.20160823-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.67-1ubuntu0.16.04.2
version.libgl1-mesa-dri: libgl1-mesa-dri 11.2.0-1ubuntu2.2
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 11.2.0-1ubuntu2.2
version.nvidia-graphics-drivers: nvidia-graphics-drivers-* N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.18.3-1ubuntu2.2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.1-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.7.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20160325-1ubuntu1.1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau N/A
xserver.bootTime: Fri Oct 14 17:02:15 2016
xserver.configfile: /etc/X11/xorg.conf
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.18.3-1ubuntu2.2

[Paul White (paulw2u)]

We are sorry that we do not always have the capacity to review all reported bugs in a timely manner. You reported this bug some time ago and there have been many changes in Ubuntu since that time.

Ubuntu 16.04 (xenial) reached end-of-life on April 29, 2021.

Do you still see a problem related to the one that you reported when using a currently supported version of Ubuntu? Please let us know if you do otherwise this report can be left to expire in approximately 60 days time.

Thank you for helping make Ubuntu better.

[Paul White (paulw2u)]

No response from reporter so closing as 'Invalid'.