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How to stop W7 arbitrarily changing screen resolutions



 
 
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  #1  
Old February 17th 19, 01:46 PM posted to alt.windows7.general
Java Jive
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Posts: 391
Default How to stop W7 arbitrarily changing screen resolutions

I have a laptop in a docking station, which is convenient because
various cables such as the network lead, mouse, and keyboard connect to
the dock rather than the laptop, so I can just lift the laptop out of
the dock and carry it elsewhere, sometimes even to another dock.

The problem is that none of the docks have a monitor plugged into them
- mine caught fire, literally, about 9 months ago, and as the only
desktop PCs I have were running W2k and I'm short of cash, I didn't
think it was an urgent matter to replace it - so Windumb defaults the
screen resolution to 1024x768, whereas the laptop's native resolution is
1440x900, which is what I want to use. Even if I set the resolution to
1440x900, if the account times out and locks, or I close the lid to
hibernate, when I next log back in all the windows have been rammed into
the top-left corner and reduced in size, because either at the log in
screen or between it and the user's resolution preference being set,
Windumb has defaulted the resolution back to 1024x768.

How can I tell Windumb to use *ONE* screen resolution across the entire
platform - login screen, default user resolution (and disallow the
user from changing it), etc - as in the good old days?
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  #2  
Old February 17th 19, 07:02 PM posted to alt.windows7.general
Paul[_32_]
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Posts: 11,873
Default How to stop W7 arbitrarily changing screen resolutions

Java Jive wrote:
I have a laptop in a docking station, which is convenient because
various cables such as the network lead, mouse, and keyboard connect to
the dock rather than the laptop, so I can just lift the laptop out of
the dock and carry it elsewhere, sometimes even to another dock.

The problem is that none of the docks have a monitor plugged into them
- mine caught fire, literally, about 9 months ago, and as the only
desktop PCs I have were running W2k and I'm short of cash, I didn't
think it was an urgent matter to replace it - so Windumb defaults the
screen resolution to 1024x768, whereas the laptop's native resolution is
1440x900, which is what I want to use. Even if I set the resolution to
1440x900, if the account times out and locks, or I close the lid to
hibernate, when I next log back in all the windows have been rammed into
the top-left corner and reduced in size, because either at the log in
screen or between it and the user's resolution preference being set,
Windumb has defaulted the resolution back to 1024x768.

How can I tell Windumb to use *ONE* screen resolution across the entire
platform - login screen, default user resolution (and disallow the
user from changing it), etc - as in the good old days?


This utility is capable of taking a "real time" PNP reading
from the hardware, as well as showing a value in the registry
recorded against a device.

https://www.entechtaiwan.com/util/moninfo.shtm

How it's supposed to work (roughly), is laptop panels don't
have an EDID. Instead, there is some sort of fakery provided
by the BIOS or something. The BIOS has ACPI tables, and is
able to pass a good deal of information as a standardized set of
PNP-like informations. The manufacturer can add a table at
manufacturing time, that declares the dimensions of the LVDS
interface LCD panel.

If you have a laptop model with two panels as possible product
fittings (say a 1366 and a 1920 HD option), then if you put
the wrong panel in as a replacement, you get black bars on two sides.
This is because the BIOS is set up for 1366, and when a 1920 panel
is installed, the PNP is still indicating 1366. And I don't know
if that one is easy to fix either - other than some sort of
BIOS or utility trick from the chipset maker. (Video drivers
have overrides for regular monitors, so you can select
values not in the EDID table. As can Entechtaiwan Powerstrip,
a product no longer for sale.)

Regular monitors are better, in that being portable and
self-sufficient devices, they have a "datapath" on the cable,
plus a one-way serial channel. The serial channel is DDC and
reads an EDID EEPROM. The EEPROM should really be read-only,
but some (unfortunately) also support write and get damaged
while the user is using the monitor.

The EDID gives a table, including a max (native) resolution
for usage. The video card has the serial bus to read this.
And that's what "moninfo" utility is using in real time.
At least for a real monitor, it can command the video card
to check the serial bus and read the table.

More than 20 years ago, they used to make monitors that
were not multisync. The monitors had only one modeline
value. If you connected a multisync OS to a single sync
monitor, and commanded 135Hz refresh rate, you could
destroy the monitor. Naturally, this led to the notion
of lawsuits and class action suits.

As a result of those unfortunate incidents, the video
card drivers have a policy. They won't use "excessive" VESA
settings unless they have proof in the form of an EDID table.
The consideration would be, for example, that 1024x768 or
1152x870 might be "safe" as those were values used by the
"monitors that could fry".

Projectors with VGA interfaces, for reasons known unto themselves,
didn't have EDID and DDC/CI serial clock and data. They just
had RGBHV. And that's kinda what your symptoms are like.
Your inability to hold a resolution, could be related
to a lack of EDID PNP info useful for "guaranteeing"
that the res you selected is safe. It would be normal for
the office "projector" for meetings, to revert to 1024x768 @ 60Hz.

It could be, that for some reason, your CurrentControlSet
is reverting to one of the backup sets, at every boot,
and it's somehow related to a behavior like that. It's
less likely that whatever table the BIOS passes in lieu
of the LCD panel (LVDS) is not getting passed properly.

Connecting to a dock, can cause "new hardware detections".
But if the dock doesn't actually touch the internal VGA
interface from the chipset, I fail to see how that should
throw off a resolution setting, or fool the chipset graphics
to be running dual panels without an LCD panel connected
to the dock.

As for locations in the registry, it's tricky. The various
monitor types and classes, are actually stored in different
places. It's not necessarily true that two set of tables
"live near one another". The guy at Entechtaiwan knows
where those registry locations live, and I don't. I've
looked before, but not been able to reliably track
them down. But today, with Process Monitor (procmon),
a person could certainly start a trace, and capture
some registry operations that way, and see if they
can detect a key which is getting written, while playing
with the Display Control Panel.

Automatic detection of connected displays (by impedance sensing),
probably started close to 20 years ago, and the price we
pay for that, is constant changes to settings. Powerstrip
could be used to set a modeline (for say your office projector),
but I don't know if Powerstrip actively hammers the Registry
when you plug and unplug stuff. Since the office projector
doesn't have DDC, there can't even be a product branding
showing in the table, like "Bell and Howell". A 1024x768
projector would be "generic display device" or similar.

Good luck,
Paul
 




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