Created attachment 33719 [details]
Bug detailed description:
With bug#14611 fixed and enable VGA output by kernel option, we can start X without monitor connected. But there also have problem as following described:
Start machine with monitor attached. After kernel booting, disconnect monitor and then start X. Running glxgears, we find the running status is wrong. Connecting monitor again, we can see the running 3D window is blank screen. If start X first and then disconnect monitor, glxgears works well.
There is another condtions: Start machine without monitor attached. After kernel booting, then start X, glxgears also works fine.
1.enable VGA output with kernel option in the grub: video=VGA-1:e
2.reboot machine with monitor connected
3.disconnect monitor before starting X
Created attachment 33721 [details]
glxgears window is blank sceen if disconnect monitor before staring X
the symptom is glxgears doesn't print info like fps, and shows blank if we re-connect the monitor.
Created attachment 33741 [details]
I think this is caused by the glxgears swap waiting for an event that will never occur. I need to add better error handling for that case.
Can you try this patch?
With this patch, it still fails on G33. But I find it works well on G45 now without this patch. I will make further test on other machines.
Does this still happen with the latest bits?
Tested on G45 and G33, it works fine.
Thanks for the update.
Closing old verified.