[SOLVED] Welcome screen flickers, desktop works fine

[demalex]

Hello all,

I have a very annoying problem with the following setup:

Dell Inspiron 17R SE with Nvidia 650M (Optimus)
Linux Mint 15 KDE
Bumblebee - installed and working (tested with 'optirun glxspehres')
23" external monitor connected via HDMI cable

The problem is that Welcome screen is flickering after system boot. It looks like refresh rate is too small plus some small vertical vibration. After I log in, the screen is still flickering but right after tools icon loads (after hdd icon on startup screen) the screen goes black for 1-2 seconds and then back to normal with NO flickering. Additional icons (internet, desktop, etc) and then the desktop itself are loaded normally without flickering. Looks like at some point during session startup the system loads required modules or settings which eliminate flickering.

What I tried so far:

1. disconnected external monitor and used notebook's display - no flickering

2. connected external monitor via VGA cable - no flickering

3. connected via other HDMI cable - screen flickers

4. blacklisted snd_hda_intel module - still flickering

How can I detect what happens when the screen goes black and then back to normal during session startup, thus eliminating the flickering?

Any ideas?

[demalex]

I managed to solve the problem with flickering by explicitly turning off notebook's display and making HDMI monitor primary output in /etc/mdm/Init/Default :

mode="$(xrandr -q|/bin/grep -A1 "HDMI1 connected"| tail -1 |awk '{ print $1 }')"
if [ -n "$mode" ]; then
xrandr --output LVDS1 --off
xrandr --output HDMI1 --primary --auto
fi