Ubuntu
linux package

  1. Bug #1275794
  2. Comment #111

Comment 111 for bug 1275794

Revision history for this message
In , K-stefan (k-stefan) wrote :

I'm not an expert in this field, but as far as I can interpret the debug output, its only related to the kernel. It seems to be related to link training, whatever that exactly means. My main setup is using an HDMI monitor, so I started with that. I added more and more debug output and ended with what I have in link-train-debug.patch.

With that patch HDMI takes about 30 seconds and then I see output. But sometimes, it doesn't work at all (see with-link-train-debug-hdmi-3.13.0-ARCH-local-dirty.txt).

However, when I attached a DP monitor at it, switching worked almost instantly (see with-link-train-debug-dp-3.13.0-ARCH-local-dirty.txt).

I then traced down the "offending" debug print, and replaced it with a delay (see link-train-delay.patch). It seems to work on my setup. I tested docked and docking while on, in both cases I get display output almost immediately...

While I don't understand that stuff really, it seems to be a problem of reading the link status, at least with that delay, reading it seems to heal the problem, at least for DP...