The screen backlight flickers at random intervals (sometimes 5 times per second, sometimes once per 5 seconds, irregular pattern, once per second average). I recorded samples and put some diagnostic files here: http://aboei.de/flicker.zip These files will be deleted on April 1st, 2015.
I was not able to solve this, tried newer and older kernels, newer X. Tried fglrx: card seems to be not supported.
Issue is also present when booting from vanilla Mint 17.1 Cinnamon installation media (DVD).
inxi -F reports driver ati,radeon, no errors in dmesg, Xorg.0.log, ... reports 68.9MHz, 1280x800@60 for LVDS, no other screens connected ... Well, mostly: in Xorg.0.log there are two relevant mode line versions (note the refresh rate difference):
Code: Select all
[ 136.760] (II) RADEON(0): Printing probed modes for output LVDS
[ 136.760] (II) RADEON(0): Modeline "1280x800"x60.0 68.94 1280 1296 1344 1408 800 801 804 816 -hsync -vsync (49.0 kHz eP)Code: Select all
[ 157.840] (II) RADEON(0): Printing DDC gathered Modelines:
[ 157.840] (II) RADEON(0): Modeline "1280x800"x0.0 68.94 1280 1296 1344 1408 800 801 804 816 -hsync -vsync (49.0 kHz eP)Same with vanilla Ubuntu 14.04.1 LTS 64bit. While installing it, Live DVD uses an oder Kernel which doesn't use gfx acceleration - no flicker there. After Updating Kernel, flicker is back.
debian 7.7 uses an older Kernel (3.2) ... no flicker: there's a error initializing the card (acceleration not used).
Did not flicker when MS Vista was installed a day before.
Any idea what could be causing this flicker? Any hint what I could try next? Or what to report here to narrow down the issue?