Screen goes black at random intervals

opensuse v11.3
linux x86_64
ati radeon hd3200 (builtin to mb)
fglrx driver - distribution-specific build

At random intervals the video output is turned off for 2 - 3 seconds giving a black screen. (I suspect the 2 - 3 second blank time is how long it takes the monitor to recover after a loss of input signal.) The interval between events can vary from 1 minute to an hour to more than a week, and recently more than a month. Sometimes I get several per hour; other times not for two weeks. Hmm, there was a kernel update in the last week or so…

At one time the cause was pointed at a USB driver problem since a number of USB log entries occurred at the same time as the screen blanking. That is not the case here; there is nothing in </var/log/messages> (or the dmesg output) that is anywhere near when a screen event happens.

It is annoying. Has anyone else seen this?

On 2010-11-24 23:06, jimoe666 wrote:

> It is annoying. Has anyone else seen this?

It smells of cable or connection problem

Cheers / Saludos,

Carlos E. R.
(from 11.2 x86_64 “Emerald” at Telcontar)

Yes it happens to my Laptop and two desktops usually right after I have done several hours per day of heavy work, then I get about a week of these annoying blank screens progressively deminishing until the next time I run a machine heavy. I can say it wasn’t there in 11.1 32bit, was there in 11.1 64bit, is there with 11.2 32bit. After heavy use I now reboot about 3 to 4 times and they go away for quite a while.

I haven’t seen an openSUSE bug report for this behaviour, but there seems to be plenty of online references to this issue across various distros and hardware platforms. FWIW, I found this Fedora [bug report](bug report) which seems to match the problems you guys describe, with the gnome power manager being pointed to as a likely culprit. (I’m not sure what DE either of you are using, so this may not be relevant). A similar (Fedora-based) discussion here. KDE4 power management is also mentioned.

I didn’t issue a bug report, but I kinda figured it was something to do with power management in KDE4.x.x simply because I noted a difference in the frequency of occurrence based upon using battery vs power and during battery full as opposed to battery depleted. While the laptop exhibits the most pronounced effect, the desktops are affected. So I am leaning towards 2 culprits, screensaver & powermanager as they both use ACHI. While on the subject of ACHI, I do note that during kernel load there is a complaint about ACHI not found but then a second statement appears saying it is using the ACHI !!??

I’ve never experienced this behaviour, but have you tried adjusting the KDE4 power management settings?

System Settings > Advanced > Power Management > Edit Profiles (check the screen blanking settings there)

It may be that there are some rogue settings in your current config.

Yes I have. I even set the screen never to blank (no blank option in bios, no power management in bios to limit brilliance, KDE4 set same) Check the KDE settings and found no rogue values in files either. Made no difference.