> ------- Original Message -------
> On Wednesday, May 25th, 2022 at 10:31 PM, Keith Lofstrom <[email protected]> 
> wrote:

>...
> Anyway ... My real problem is that video cards (not Linux
> or other OS) are designed to reconfigure into basic 1024x768
> VGA mode (not rotated like my screens) if they are not
> getting EDID (Extended Display Identification Data) from
> the display.
>...

On Fri, May 27, 2022 at 10:42:48PM +0000, Ben Koenig wrote:
> As interesting as this all is, I prefer to use the tools for their intended 
> purpose. xrandr is powerful when working with dynamic and constantly changing 
> monitor environments. In particular for laptops where you don't have a lot of 
> control over the secondary display. For a less mobile use case (e.g. a 
> desktop system where the monitors never change) I prefer to fall back on the 
> traditional xorg.conf.
...
> In my preferred linux distro, the advice from 2008 is still relevant. 
> Manpages are also still relevant, and sometimes you just gotta tell people to 
> RTFM.
...
> -Ben

RTFemail ...

Indeed, I spent almost a week attempting to fight the
problem with xorg.conf.  I left that (and *MANY* other
attempts) out of my email because it was already too long.

Ben's suggestion may be a good one in many circumstances
...  but I could not figure out how to use xorg.conf to
*continuously* re-re-reconfigure the videocard (or at least
the four videocards that I tried).  The videocard changes
its display configuration all by its lonesome when EDID
information stops arriving from the monitor.  As it should;
without a default display mode, install configuration and
system recovery is too hard. 

Because of the inherent behavior of display cards, this is
not a "fire and forget at boot time" configuration issue.

Perhaps I was not using "DefaultModes 1" properly, which
is the only part of the xorg.conf man(5) page that seemed
vaguely germane to EDID.  I've seen other references to
EDID on some webpages, one mentioned:

Option         "CustomEDID"

... added to Section "Device" the xorg.conf file. 

But again, I don't understand how that forces the video
card itself to freeze in the desired mode, even if the
display is absent for minutes or hours, "KVM'ed" to a
different computer, or not-at-all connected during a
reboot.

A "GOOD" KVM switch does remember the EDID, and I now
have a GOOD KVM for my left "master" screen, but as I
mentioned, I haven't yet found a good .V. switch (no
keyboard or mouse) for the left "auxilliary" screen.
A second iogear GCS932UB will arrive via eBay "real soon
now", but I'm not sure how that will behave without
keyboard or mouse.

Keith

-- 
Keith Lofstrom          [email protected]

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