Description of problem:

I usually work with a T460s attached to an ASUS external monitor via DisplayPort.  Occasionally (several times a day) the screen will go blank black for a couple of seconds before returning.

This seems to be associated with the kernel logging this message:

[15017.132508] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun

I've also seen these other messages, though I'm not sure if they were associated with a screen blanking event:

[14391.418060] [drm:intel_pipe_update_end [i915]] *ERROR* Atomic update failure on pipe A (start=184299 end=184300) time 151 us, min 1431, max 1439, scanline start 1429, end 1443
[14391.801776] [drm:intel_pipe_update_end [i915]] *ERROR* Atomic update failure on pipe A (start=184322 end=184323) time 171 us, min 1431, max 1439, scanline start 1428, end 1444


Version-Release number of selected component (if applicable):

kernel-4.7.3-200.fc24.x86_64
xorg-x11-drv-intel-2.99.917-24.20160712.fc24.x86_64

How reproducible:

Occasional and random

Steps to Reproduce:

Nothing specific.  Just running a MATE desktop on external monitor (laptop internal screen disabled).

Actual results:

Occasional screen blanks.

Expected results:

No screen blanks.


Additional info:

Intel inbuilt graphics in use:

$ lspci -v -s 00:02.0
00:02.0 VGA compatible controller: Intel Corporation HD Graphics 520 (rev 07) (prog-if 00 [VGA controller])
	Subsystem: Lenovo Device 2233
	Flags: bus master, fast devsel, latency 0, IRQ 126
	Memory at f0000000 (64-bit, non-prefetchable) [size=16M]
	Memory at e0000000 (64-bit, prefetchable) [size=256M]
	I/O ports at e000 [size=64]
	[virtual] Expansion ROM at 000c0000 [disabled] [size=128K]
	Capabilities: <access denied>
	Kernel driver in use: i915
	Kernel modules: i915

ASUS 2560x1440 monitor, attached via DisplayPort:

$ edid-decode /sys/class/drm/card0-DP-3/edid
Extracted contents:
header:          00 ff ff ff ff ff ff 00
serial number:   04 69 a3 27 3b 0c 00 00 06 18
version:         01 04
basic params:    a5 3c 22 78 3a
chroma info:     a5 95 aa 54 4f a1 26 0a 50 54
established:     b7 ef 00
standard:        d1 c0 b3 00 95 00 81 80 81 40 81 00 81 c0 71 4f
descriptor 1:    56 5e 00 a0 a0 a0 29 50 30 20 35 00 55 50 21 00 00 1a
descriptor 2:    00 00 00 ff 00 45 32 4c 4d 54 46 30 30 33 31 33 31 0a
descriptor 3:    00 00 00 fd 00 18 4c 18 63 1e 04 11 01 40 f8 38 f0 3c
descriptor 4:    00 00 00 fc 00 41 53 55 53 20 50 42 32 37 38 0a 20 20
extensions:      01
checksum:        22

Manufacturer: ACI Model 27a3 Serial Number 3131
Made week 6 of 2014
EDID version: 1.4
Digital display
8 bits per primary color channel
DisplayPort interface
Maximum image size: 60 cm x 34 cm
Gamma: 2.20
DPMS levels: Off
Supported color formats: RGB 4:4:4, YCrCb 4:4:4, YCrCb 4:2:2
First detailed timing is preferred timing
Established timings supported:
  720x400@70Hz
  640x480@60Hz
  640x480@67Hz
  640x480@75Hz
  800x600@56Hz
  800x600@60Hz
  800x600@72Hz
  800x600@75Hz
  832x624@75Hz
  1024x768@60Hz
  1024x768@70Hz
  1024x768@75Hz
  1280x1024@75Hz
Standard timings supported:
  1920x1080@60Hz
  1680x1050@60Hz
  1440x900@60Hz
  1280x1024@60Hz
  1280x960@60Hz
  1280x800@60Hz
  1280x720@60Hz
  1152x864@75Hz
Detailed mode: Clock 241.500 MHz, 597 mm x 336 mm
               2560 2608 2640 2720 hborder 0
               1440 1443 1448 1481 vborder 0
               +hsync -vsync 
Serial number: E2LMTF003131
Monitor ranges (CVT): 24-76Hz V, 24-99kHz H, max dotclock 300MHz
CVT version 1.1
Max active pixels per line: 2560
Supported aspect ratios: 4:3 16:9 16:10 5:4 15:9
Preferred aspect ratio: 16:9
Supports CVT reduced blanking
Supported display scaling:
    Horizontal shrink
    Horizontal stretch
    Vertical shrink
    Vertical stretch
Preferred vertical refresh: 60 Hz
Monitor name: ASUS
Has 1 extension blocks
Checksum: 0x22 (valid)

CEA extension block
Extension version: 3
30 bytes of CEA data
  Video data block
    VIC 01 640x480@60Hz 
    VIC 02 720x480@60Hz 
    VIC 03 720x480@60Hz 
    VIC 17 720x576@50Hz 
    VIC 18 720x576@50Hz 
    VIC 19 1280x720@50Hz 
    VIC 04 1280x720@60Hz 
    VIC 20 1920x1080i@50Hz 
    VIC 05 1920x1080i@60Hz 
    VIC 31 1920x1080@50Hz 
    VIC 16 1920x1080@60Hz (native)
    VIC 14 1440x480@60Hz 
    VIC 15 1440x480@60Hz 
    VIC 29 1440x576@50Hz 
    VIC 30 1440x576@50Hz 
  Audio data block
    Linear PCM, max channels 1
    Supported sample rates (kHz): 96 48 44.1 32
    Supported sample sizes (bits): 24 20 16
  Speaker allocation data block
  Vendor-specific data block, OUI 000c6e
Basic audio support
Supports YCbCr 4:4:4
Supports YCbCr 4:2:2
1 native detailed modes
Detailed mode: Clock 27.000 MHz, 597 mm x 336 mm
                720  736  798  858 hborder 0
                480  489  495  525 vborder 0
               -hsync -vsync 
Detailed mode: Clock 74.250 MHz, 597 mm x 336 mm
               1280 1390 1430 1650 hborder 0
                720  725  730  750 vborder 0
               +hsync +vsync 
Detailed mode: Clock 74.250 MHz, 597 mm x 336 mm
               1280 1720 1760 1980 hborder 0
                720  725  730  750 vborder 0
               +hsync +vsync 
Detailed mode: Clock 27.000 MHz, 597 mm x 336 mm
                720  732  796  864 hborder 0
                576  581  586  625 vborder 0
               -hsync -vsync 
Checksum: 0x96 (valid)

EDID block does NOT conform to EDID 1.3!
	Detailed block string not properly terminated