[CentOS] video problem since 2015-04-01 update

Fri Apr 3 17:30:21 UTC 2015
Francis Gerund <ranrund at gmail.com>

Hello!

No updates for days until 2015-04-01.  Then presented with huge steaming
pile of updates all at once, apparently related to Centos 7.1 release.

Not thinking about it being April Fools Day, I immediately did:

yum -v check-update, then

yum -v update

then rebooted.

After reboot, there is a problem with the video.  It seems to flicker when
the mouse pointer touches the screen edges.  Also, sometimes when viewing
pages in Firefox, the window becomes partially covered with horizontal
black lines.

During reboots, before the login screen appears, there are quickly
disappearing messages seeming to include references to "drm:9" and some
sort of "underrun".

In the terminal window, I get a message:

ABRT has detected 3 problem(s). For more info run: abrt-cli list --since
1428078184

When I do that, I get:

id (blah, blah)
reason:         WARNING: at drivers/gpu/drm/i915/intel_display.c:869
intel_wait_for_vblank+0x211/0x220 [i915]()
time:             Fri 03 Apr 2015 11:41:49 AM CDT
cmdline:        BOOT_IMAGE=/vmlinuz-3.10.0-229.1.2.el7.x86_64
root=UUID=(blah, blah) ro vconsole.keymap=us
vconsole.font=latarcyrheb-sun16 rhgb quiet LANG=en_US.UTF-8
count:          1
Directory:      /var/tmp/abrt/oops-2015-04-03-11:41:49-590-0

id (blah, blah)
reason:         WARNING: at drivers/gpu/drm/i915/intel_display.c:869
intel_wait_for_vblank+0x211/0x220 [i915]()
time:             Wed 01 Apr 2015 12:02:12 PM CDT
cmdline:        BOOT_IMAGE=/vmlinuz-3.10.0-229.1.2.el7.x86_64
root=UUID=(blah, blah) ro vconsole.keymap=us
vconsole.font=latarcyrheb-sun16 rhgb quiet LANG=en_US.UTF-8
package:        kernel
count:          11
Directory:      /var/tmp/abrt/oops-2015-04-01-12:02:11-1220-1
Reported:       cannot be reported

id (blah, blah)
reason:         WARNING: at drivers/gpu/drm/i915/intel_display.c:869
intel_wait_for_vblank+0x211/0x220 [i915]()
time:             Fri 03 Apr 2015 11:41:49 AM CDT
cmdline:        BOOT_IMAGE=/vmlinuz-3.10.0-229.1.2.el7.x86_64
root=UUID=(blah, blah) ro vconsole.keymap=us
vconsole.font=latarcyrheb-sun16 rhgb quiet LANG=en_US.UTF-8
Directory:      /var/tmp/abrt/oops-2015-04-03-11:41:49-590-1
Reported:       cannot be reported


The Autoreporting feature is disabled. Please consider enabling it by
issuing
'abrt-auto-reporting enabled' as a user with root privileges.



So is this line where the problem may be?:

drivers/gpu/drm/i915/intel_display.c:869 intel_wait_for_vblank+0x211/0x220
[i915]()

Started to search online for information, but quickly decided:

1)  available info is over my head

2)  when in a hole, stop digging

So, any obvious answers, other than a complete reinstall?

Note: I really thought Centos is about reinstalling after years, not
months.  Grrr . . .