Ticket #8893 (new defect)

Opened 6 years ago

Last modified 4 years ago

DCON display glitches when unfreezing

Reported by: wad Owned by: jg
Priority: high Milestone: 1-software-later
Component: x window system Version: not specified
Keywords: Cc:
Action Needed: code Verified: no
Deployments affected: Blocked By:


Using build 767, with "Automatic power management" enabled (not "Extreme power management") there is glitch (vertical jump) every time the machine switches from the DCON back to the primary display controller.

Change History

Changed 6 years ago by mstone-xmlrpc

  • keywords cjbfor9.1.0 added
  • milestone changed from 8.2.1 to 9.1.0

Pushing out to 9.1.0, per edmcnierney's request.

Changed 5 years ago by dsd

  • next_action changed from never set to diagnose
  • component changed from x window system to hardware
  • summary changed from Display glitches when resuming to DCON display glitches when resuming
  • milestone changed from 9.1.0 to 1.5-F11

moving to XO-1.5 milestone as we also have the issue there and we've been discussing this (plus #9664) recently.. can we do anything?

Changed 5 years ago by dsaxena

I'm running OS40 and don't see this glitch in "while true; do echo mem > /sys/power/state; done" loop.

Changed 5 years ago by triagebot

  • keywords cjbfor9.1.0 removed
  • priority changed from normal to high
  • milestone changed from 1.5-software to 1.5-software-final

changed by irc user Quozl:

Changed 5 years ago by dsd

I can reproduce this on os54 on my B3.

The following bash loop causes the whole screen to 'pulse':

while true; do
	echo 1 > /sys/devices/platform/dcon/freeze
	sleep 0.2
	echo 0 > /sys/devices/platform/dcon/freeze
	sleep 0.2

It is not severe, but is still a bit disorientating

Changed 5 years ago by Quozl

I also can reproduce using that method. Gross glitches are seen rarely; of the order of minutes apart, and cause an image shift of hundreds of pixel rows. Minor glitches are seen about every two seconds. The minor glitches may be more visible as periods of brightness if the screen is viewed from the touchpad (lift the front of the keyboard until it nearly obstructs your vision).

Changed 5 years ago by dsd

  • summary changed from DCON display glitches when resuming to DCON display glitches when unfreezing

Changed 5 years ago by wad

  • next_action changed from diagnose to code
  • component changed from hardware to x window system
  • milestone changed from 1.5-software-final to 1.0-software-update

Can we please not reuse XO-1 tickets for XO-1.5 bugs ?

#9869 contains the XO-1.5 version of this bug.

This is not a hardware bug, despite the gross inefficiencies of the DCON (see #1671 for a summary). It worked better on earlier versions of X.

Changed 4 years ago by dsd

  • milestone changed from 1.0-software-update to 1.0-software-later
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