Comment 182 for bug 561802

CVTECH (cvtech) wrote :

I have access to qty3 E6410ATGs with the 1280x800 display (reports itself as "seiko-epson corporation 14"), only one is experiencing this issue and this is after update manager updating from the base Ubuntu 10.04.1 installation with 2.6.32-24 kernel. The machine having troubles is a core5-i540 vs core5-i520 on the other two machines not having troubles.

The symptoms are very similar to post #168. The machine worked fine until updating a couple days ago. Included in the update was update from kernel 2.6.32-24 to 2.6.32-26 but I suspect this is not the issue for reasons I will explain.

I am experiencing similar issues to post #168. At login screen after updates including the 2.6.32-26 kernel the blank screen happens. Plugging in any external monitor (on Dsub 15 pin, or DisplayPort) instantly the internal monitor will come to life. So the workaround is to pick the kernel from Grub, wait for the blank screen which would normally be the login/welcome screen on Ubuntu, quickly plug in a cable (there is about a 5 second window that this works), then unplug the cable and now you can take the laptop and walk around the house like you wanted to in the first place when you bought a laptop. This is very reliable, with about 96 of 100 reboots (hot or cold) able to start the internal display by plugging a monitor cable in (Dsub or Displayport, doesn't matter). The other 4 reboots vary from won't work (maybe took too long to plug) to about 1 in 100 will randomly just boot without needing the cable plug procedure!

 I note also that the monitor must be present but not required to be powered on, an unterminated cable does not have the same effect. So, something in the process sees the presence of a new external monitor connection and this then triggers the internal monitor to come on (at correct resolution) as DP1 and everything is good after that until the next reboot, even after disconnecting the external cable.

I suspect something has changed unrelated to the kernel update. The reason is that the two machines I have that are working fine one is running 2.6.32-24, the other 2.6.32-25. The machine having problems was working fine on 2.6.32-24 and started having issues immediately after the update (via update manager) that included 2.6.32-26 amongst many other things. I removed (via package manager) the 2.6.32-26 kernel image and headers and installed the 2.6.32-25. This did not solve the issue and now even if I boot (from grub) the old previously working 2.6.32-24 or the 2.6.32-25 kernel that works on another machine the same issue happens on the problem machine, even in recovery mode!

I am reasonably familiar with Ubuntu as a user, but no idea how to gather info to track this down. If someone has an idea of a path to follow, then let me know how to compile logs or config files I can gather info from the working (2.6.32-25) vs non-working (2.6.32.-25) machines, only difference being i520 vs i540 processors.

These are live (not development) machines so unfortunately I can't try too much in the way of installing source code and patches but on the third machine if we can come up with a way to replicate the problem, it can be a total sandbox to test anything out.

I note also that this is the "Daylight Viewable" E6410 ATG display which has a max resolution of 1280x800 and when working is correctly identified by xrandr on DP1. Dell makes the E6410 with at least 1 other display.

Also intel graphics gma4500 (i915) on all machines and kernels noted are the "-generic" versions.