Ubuntu 16.04HWE kernel 4.10.0-30
libdrm2 version 2.4.76-1~ubuntu16.04.1
lspci excerpt:
00:02.0 VGA compatible controller: Intel Corporation Device 193d (rev 09)
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI]
Amethyst XT [Radeon R9 M295X]



kern.log, syslog and dmesg are flooded with messages like:

[213775.374922] [drm:drm_mode_addfb2 [drm]] [FB:78]
[213775.393105] [drm:drm_mode_addfb2 [drm]] [FB:76]

(always alternating between FB:78 and FB:76)

About 60 such messages per second are issued.
This causes above named log files to grow into Gigabyte range, make them
unusable and cause critical disk shortages on the root filesystem.

Please provide a fix or method to stop these messages.