[ubuntu-za] blank screen with KVM switch

[Charl Wentzel]

On Mon, 2010-12-06 at 13:33 +0200, Charl Wentzel wrote:
> On Fri, 2010-12-03 at 18:17 +0200, Gustav H Meyer wrote:
> > I've had the same problem before but forgot the details but it was
> > also not a USB KVM. The basics that you need, if I rememeber
> > correctly, is to get the EDID values of your monitor with read-edid
> > and set it manually with xrandr when you connect the device or
> > something like that. You may have to use google to find the details.
> > 
> 
> > On Fri, Dec 3, 2010 at 3:24 PM, Charl Wentzel
> > <charl.wentzel at vodamail.co.za> wrote:
> >         I just swapped my trusty PS/2 KVM for a USB KVM with one
> >         unfortunate
> >         side-effect... when I boot my PC with the screen connected via
> >         the KVM I
> >         get a blank screen.  With the screen connected directly
> >         everything
> >         works.
> 

Hi Gustav

It seems the problem is not so much with the edid data, but maybe with
xrandr.  To see if the edid data is corrupted by the KVM I used both
get-edid and xrandr and got different results:

a. get-edid
Whether I connect the monitor directly or via the KVM, get-edid detects
the monitor correctly.

b. xrandr
When I connect the monitor directly it reports the monitor as
"connected" and displays its edid information.  When I connect the
monitor via the KVM it reports the monitor as "disconnected" with no
edid information, even though I'm using the monitor.

It seems get-edid and xrandr is affected differently by the KVM?!  Maybe
there's a bug in xrandr?

Charl