Comment # 5
on bug 89420
from Benjamin Bellec
I have the same powersave issue with a Dell U2414H (1920*1080). It's a simple
monitor setup (only one screen plugged to the videocard).
On a Radeon HD5850 or a GeForce GTX 950 (both with free drivers), my
motherboard POST is displayed, but when Fedora begins to load the screen goes
to powersave. I have to unplug and plug again the DisplayPort cable on the
videocard to get the screen back. Note that if I remember well, sometimes it
works perfectly.
The problem also occurs when I reboot the computer from Fedora, then the screen
stays in powersave mode, I don't even see the motherboard POST.
The screen is plugged with a DisplayPort (to videocard) <--> MiniDisplayPort
(to the screen). This is cable which comes with the screen. The screen is
configured in DP1.1a mode. I can switch to DP1.2 with the OSD screen menu, in
that case the Radeon seems to handle it (though the powersave issue remains)
but the GeForce card get not more screen at all.
I just got a second screen from Dell RMA, and the problem remains.
My config:
Fedora 23 (x86-64)
kernel 4.4.6-300.fc23.x86_64
libdrm 2.4.66-1.fc23
Please please fix it, this is a really boring issue :(