[Intel-gfx] Dell U2412M monitor complains about input timing

[Jesse Barnes]

On Mon, 08 Jul 2013 21:38:13 -0700
Christian Kreibich <christian at whoop.org> wrote:

> Hi all,
> 
> I hope I have found the right forum for asking my question -- apologies
> if that's not the case. I have a Dell U2412M connected to a Dell
> StudioSlim 540s, with the i915 driver on Fedora's 3.9.6 Kernel running
> KDE (4.10.4). The monitor is connected via an HDMI cable, with a DVI
> adapter to the monitor. When booting up my machine into X or waking it
> from sleep, things work perfectly. However, when I turn off the monitor
> (or whenever it turns itself off, if configured to do so) while the PC
> keeps running, I have a hard time getting the monitor to work when
> turning it on again. One of three things happens:
> 
> (1) The monitor pops up a message saying that "The current input timing
> is not supported by the monitor display. Please change your input to
> 1920x1200 at 60Hz".
> 
> (2) The expected desktop contents appear on screen, but only for a
> fraction of a second. Then the monitor goes blank again for a few
> seconds, and this iterates until I turn it off again.
> 
> (3) Things work as expected, but unfortunately only after turning the
> monitor on and off on the order of a dozen times. Even then, the
> configuration is a bit wonky (for example, xrandr shows all connections
> disconnected).
> 
> I have the monitor configured to 1920x1200 at 60Hz both in KDE's settings
> and via variations of an xorg.conf (including no xorg.conf) in which I
> expressly state that this is what my monitor needs.
> 
> I'm wondering if the problem might be HDMI-related and whether it sounds
> familiar to folks on this list. Any help is welcome.

Sounds like our pixel clock is probably out of the range your monitor
wants.  If you can get that mode running with the VESA driver you could
collect a register dump in the good and bad cases so we could compare...

-- 
Jesse Barnes, Intel Open Source Technology Center