Comment 4 for bug 912992
Revision history for this message
| Bryce Harrington (bryce) wrote Re: Primary laptop display not working, external monitor works fine. | #4 |
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1b1ed1a
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Interesting! Well, the logs look ok; your system is seeing your monitor and graphics card capabilities just fine, and the logs look perfectly normal. Which, obviously, is a blatant lie.
Now, you have sandybridge graphics, and we certainly have had some reported issues with graphics on these systems. I think the CRTC mapping may be off in some situations. Fortunately these types of issues are getting high priority attention upstream, if we can collect the right info.
Enable drm debugging. Run `sudo xdiagnose`, it's the first checkbox. Enable it, hit apply, wait for grub to rebuild, then reboot and collect `sudo dmesg > dmesg.txt` and post that here. We can review that to see if it is a CRTC mapping issue.
It sounds like you're currently running an earlier version that does not have this bug? If so, please collect 'xrandr --verbose > xrandr.txt` from that earlier version and post that here too. We can review that to see if it is an EDID/modeline issue.
With an external monitor attached, run the command `xrandr --output LVDS1 off; xrandr --output LVDS1 --auto` which will see if simply re-loading the display is enough to get it initialized properly.