blank a screen

NTDEV
1

Hi All,

Is it possible to blank a monitor from driver code. The solution should be
independent of the display adapter we use! Its something like what OS does
to the screen on Hybernate/Standby.

Any information is helpful.

Regards,
Kedar

2

Kedar,

Without knowing which display adapter it is, you’d probably have a hard
time. When the OS goes into Standby or Hibernate, it actually calls the
display driver with a DrvAssertMode(FALSE) and DrvDisablePDev() to disable
the screen.

Now the question is of course what you’re actually trying to achieve? If
you just want a blank screen, you could of course just have a user app that
occupies the whole screen area and draws it black (or whatever colour you
like). That would be easy and not require any particular difficult setup.

The protocol for stating power management to the display driver (or
miniport in this case) is unfortunately not available in a “public
interface”. It used to be, in Windows NT4, that the call was an IOCTL,
which would have been able to anyone that can get a handle to the device,
but now it’s a “function pointer” type interface, so the driver gives a
function pointer to the OS, and the OS calls that function when it sees
fit.

I don’t know if there is an interface to call the OS to get it to call the
driver. Maybe someone else will have some ideas on that.

–
Mats

xxxxx@lists.osr.com wrote on 09/07/2004 10:51:59 AM:

Hi All,

Is it possible to blank a monitor from driver code. The solution should
be
independent of the display adapter we use! Its something like what OS
does
to the screen on Hybernate/Standby.

Any information is helpful.

Regards,
Kedar

Questions? First check the Kernel Driver FAQ at http://www.
osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@3dlabs.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

ForwardSourceID:NT00002D5E

3

YOUR DRIVER SHOULD NEVER ASSUME ANYTHING ABOUT A DISPLAY! You could be
running on a headless server or on a system with multiple terminal sessions,
how are you going to handle these. If this is in response to user event, do
you want to blank the console where user A is sitting, when the event came
from user b on the terminal session?

IF YOU DO THIS PLEASE BE SURE TO IDENTIFY YOUR FIRM AND THE PRODUCT THIS IS
FOR, SO WE CAN ALL AVOID BUYING IT.

–
Don Burn (MVP, Windows DDK)
Windows 2k/XP/2k3 Filesystem and Driver Consulting

“kedar” wrote in message news:xxxxx@ntdev…
> Hi All,
>
> Is it possible to blank a monitor from driver code. The solution should be
> independent of the display adapter we use! Its something like what OS does
> to the screen on Hybernate/Standby.
>
> Any information is helpful.
>
> Regards,
> Kedar
>
>
>

4

Hi,

Here is the requirement once again. All you have to do is blank the local
screen on which the piece of code is running. May be we can consider the
situation if we want to block the user/employee from doing any action oh his
system.

So this process talks to the display driver of the local machine and knows
only the display controller ( may be the video memory ) of the local machine
and does not even know things like terminal clients talking to it.

I thought we could achieve this by taking the Display card to a low power
state. This can be generic since the Power Register in the PCI configuration
space can be used to drive the card to low power mode.

Any other ideas?

Regards,
Kedar.

“kedar” wrote in message news:xxxxx@ntdev…
> Hi All,
>
> Is it possible to blank a monitor from driver code. The solution should be
> independent of the display adapter we use! Its something like what OS does
> to the screen on Hybernate/Standby.
>
> Any information is helpful.
>
> Regards,
> Kedar
>
>

5

YOU ARE STILL ASSUMING THIS IS A PERSONS SYSTEM!!! SORRY, EVEN XP NOW
ALLOWS TWO USERS, SO YOU BELIEVE IT OK FOR ME AS A TERMINAL SESSION USER TO
SCREWUP THE GUY AT THE CONSOLE?
WHAT ARE YOU GOING TO DO IF THERE IS NO DISPLAY ADAPTER? I KNOW OF A
PRODUCT THAT PULLED SHIT LIKE THIS AND CRASHED HEADLESS SYSTEMS THAT POOR
CUSTOMERS LOADED IT ONTO.

BOTTOM LINE IS YOUR CONCEPT IS BEYOND FLAWED. DON’T DO IT.

–
Don Burn (MVP, Windows DDK)
Windows 2k/XP/2k3 Filesystem and Driver Consulting

“kedar” wrote in message news:xxxxx@ntdev…
> Hi,
>
> Here is the requirement once again. All you have to do is blank the local
> screen on which the piece of code is running. May be we can consider the
> situation if we want to block the user/employee from doing any action oh
his
> system.
>
> So this process talks to the display driver of the local machine and knows
> only the display controller ( may be the video memory ) of the local
machine
> and does not even know things like terminal clients talking to it.
>
> I thought we could achieve this by taking the Display card to a low power
> state. This can be generic since the Power Register in the PCI
configuration
> space can be used to drive the card to low power mode.
>
> Any other ideas?
>
> Regards,
> Kedar.
>
>
> “kedar” wrote in message news:xxxxx@ntdev…
> > Hi All,
> >
> > Is it possible to blank a monitor from driver code. The solution should
be
> > independent of the display adapter we use! Its something like what OS
does
> > to the screen on Hybernate/Standby.
> >
> > Any information is helpful.
> >
> > Regards,
> > Kedar
> >
> >
>
>
>

6

Just doing “low power” on the PCI bus will lead to catastrofic failure of
the graphics card if it’s anything like a modern one, since the card
basicly has a load of processing capacity, and if the driver isn’t in on
the “we’re shutting down”, all sorts of nasty things may/will happen. Sure,
you’ll get a blank screen, at least for a little while, until the machine
reboots ;-). For this idea to work, the display driver and the
corresponding miniport absolutely has to be in on the idea of shutting down
the screen, assuming you actually want the system to be able to recover
from this state.

Now, let’s see if I understand this correctly. Joe is sitting at his desk,
and instead of wriitng code or punching numbers into the accounting
software, he’s playing quake. So you blank the screen and turn on the big
alarm to his boss, is that the idea? Wouldn’t it be better to just stop the
offending application by killing it hard?

Alternatively, have a service process in user-mode that just does a “Draw
big black rectangle” over the screen.

–
Mats

xxxxx@lists.osr.com wrote on 09/07/2004 12:16:13 PM:

Hi,

Here is the requirement once again. All you have to do is blank the local

screen on which the piece of code is running. May be we can consider the
situation if we want to block the user/employee from doing any action oh
his
system.

So this process talks to the display driver of the local machine and
knows
only the display controller ( may be the video memory ) of the local
machine
and does not even know things like terminal clients talking to it.

I thought we could achieve this by taking the Display card to a low power

state. This can be generic since the Power Register in the PCI
configuration
space can be used to drive the card to low power mode.

Any other ideas?

Regards,
Kedar.

“kedar” wrote in message news:xxxxx@ntdev…
> > Hi All,
> >
> > Is it possible to blank a monitor from driver code. The solution should
be
> > independent of the display adapter we use! Its something like what OS
does
> > to the screen on Hybernate/Standby.
> >
> > Any information is helpful.
> >
> > Regards,
> > Kedar
> >
> >
>
>
>
> —
> Questions? First check the Kernel Driver FAQ at http://www.
> osronline.com/article.cfm?id=256
>
> You are currently subscribed to ntdev as: xxxxx@3dlabs.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com

> ForwardSourceID:NT00002D7E

7

Force “Workstation Locked”. Is it not enough?

Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
xxxxx@storagecraft.com
http://www.storagecraft.com

----- Original Message -----
From: “kedar”
Newsgroups: ntdev
To: “Windows System Software Devs Interest List”
Sent: Tuesday, September 07, 2004 3:16 PM
Subject: Re:[ntdev] blank a screen

> Hi,
>
> Here is the requirement once again. All you have to do is blank the local
> screen on which the piece of code is running. May be we can consider the
> situation if we want to block the user/employee from doing any action oh his
> system.
>
> So this process talks to the display driver of the local machine and knows
> only the display controller ( may be the video memory ) of the local machine
> and does not even know things like terminal clients talking to it.
>
> I thought we could achieve this by taking the Display card to a low power
> state. This can be generic since the Power Register in the PCI configuration
> space can be used to drive the card to low power mode.
>
> Any other ideas?
>
> Regards,
> Kedar.
>
>
> “kedar” wrote in message news:xxxxx@ntdev…
> > Hi All,
> >
> > Is it possible to blank a monitor from driver code. The solution should be
> > independent of the display adapter we use! Its something like what OS does
> > to the screen on Hybernate/Standby.
> >
> > Any information is helpful.
> >
> > Regards,
> > Kedar
> >
> >
>
>
>
> —
> Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256
>
> You are currently subscribed to ntdev as: xxxxx@storagecraft.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com

8

> Here is the requirement once again. All you have to do is blank the local

screen on which the piece of code is running. May be we can consider the
situation if we want to block the user/employee from doing any
action oh his
system.

Better option is to Disable both Keyboard & Mouse ( any Input device which
is present ). This will make sure user will not do anything on that system.
Even if you blank the screen, he can always use keyboard and Mouse and do
something on the system.

Regards,
Satish K.S

9

Again, think about what you are doing, there may be no keyboard, or mouse,
or the
user may be comming in via a terminal session.

–
Don Burn (MVP, Windows DDK)
Windows 2k/XP/2k3 Filesystem and Driver Consulting

“int3” wrote in message news:xxxxx@ntdev…
> > Here is the requirement once again. All you have to do is blank the
local
> > screen on which the piece of code is running. May be we can consider the
> > situation if we want to block the user/employee from doing any
> > action oh his
> > system.
>
> Better option is to Disable both Keyboard & Mouse ( any Input device which
> is present ). This will make sure user will not do anything on that
system.
> Even if you blank the screen, he can always use keyboard and Mouse and do
> something on the system.
>
> Regards,
> Satish K.S
>
>

10

He can check wheather any local Input Device is available and Disable it, so
it doesnt effect if he is comming thru Terminal session. Since his intention
is to disable the local user to prevent from doing some actions.

Regards,
Satish K.S

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com]On Behalf Of Don Burn
Sent: Tuesday, September 07, 2004 5:26 PM
To: Windows System Software Devs Interest List
Subject: Re:[ntdev] blank a screen

Again, think about what you are doing, there may be no keyboard, or mouse,
or the
user may be comming in via a terminal session.

–
Don Burn (MVP, Windows DDK)
Windows 2k/XP/2k3 Filesystem and Driver Consulting

“int3” wrote in message news:xxxxx@ntdev…
> > > Here is the requirement once again. All you have to do is blank the
> local
> > > screen on which the piece of code is running. May be we can
> consider the
> > > situation if we want to block the user/employee from doing any
> > > action oh his
> > > system.
> >
> > Better option is to Disable both Keyboard & Mouse ( any Input
> device which
> > is present ). This will make sure user will not do anything on that
> system.
> > Even if you blank the screen, he can always use keyboard and
> Mouse and do
> > something on the system.
> >
> > Regards,
> > Satish K.S
> >
> >
>
>
>
> —
> Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@liqwidkrystal.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

11

I’d love to see a piece of non-destructive code, for testing the presence of
input devices from the kernel. Please pay particular attention to headless
(i.e. coming in from a serial line), and alternative HID devices.

–
Don Burn (MVP, Windows DDK)
Windows 2k/XP/2k3 Filesystem and Driver Consulting

“int3” wrote in message news:xxxxx@ntdev…
>
> He can check wheather any local Input Device is available and Disable it,
so
> it doesnt effect if he is comming thru Terminal session. Since his
intention
> is to disable the local user to prevent from doing some actions.
>
> Regards,
> Satish K.S
>
>
> > -----Original Message-----
> > From: xxxxx@lists.osr.com
> > [mailto:xxxxx@lists.osr.com]On Behalf Of Don Burn
> > Sent: Tuesday, September 07, 2004 5:26 PM
> > To: Windows System Software Devs Interest List
> > Subject: Re:[ntdev] blank a screen
> >
> >
> > Again, think about what you are doing, there may be no keyboard, or
mouse,
> > or the
> > user may be comming in via a terminal session.
> >
> >
> > –
> > Don Burn (MVP, Windows DDK)
> > Windows 2k/XP/2k3 Filesystem and Driver Consulting
> >
> >
> > “int3” wrote in message news:xxxxx@ntdev…
> > > > Here is the requirement once again. All you have to do is blank the
> > local
> > > > screen on which the piece of code is running. May be we can
> > consider the
> > > > situation if we want to block the user/employee from doing any
> > > > action oh his
> > > > system.
> > >
> > > Better option is to Disable both Keyboard & Mouse ( any Input
> > device which
> > > is present ). This will make sure user will not do anything on that
> > system.
> > > Even if you blank the screen, he can always use keyboard and
> > Mouse and do
> > > something on the system.
> > >
> > > Regards,
> > > Satish K.S
> > >
> > >
> >
> >
> >
> > —
> > Questions? First check the Kernel Driver FAQ at
> http://www.osronline.com/article.cfm?id=256
>
> You are currently subscribed to ntdev as: xxxxx@liqwidkrystal.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com
>
>

12

Hitherto shalt thou come, but no further.

Mat

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Don Burn
Sent: Tuesday, September 07, 2004 7:30 AM
To: Windows System Software Devs Interest List
Subject: Re:[ntdev] blank a screen

YOU ARE STILL ASSUMING THIS IS A PERSONS SYSTEM!!! SORRY, EVEN XP NOW
ALLOWS TWO USERS, SO YOU BELIEVE IT OK FOR ME AS A TERMINAL SESSION USER TO
SCREWUP THE GUY AT THE CONSOLE?
WHAT ARE YOU GOING TO DO IF THERE IS NO DISPLAY ADAPTER? I KNOW OF A
PRODUCT THAT PULLED SHIT LIKE THIS AND CRASHED HEADLESS SYSTEMS THAT POOR
CUSTOMERS LOADED IT ONTO.

BOTTOM LINE IS YOUR CONCEPT IS BEYOND FLAWED. DON’T DO IT.

–
Don Burn (MVP, Windows DDK)
Windows 2k/XP/2k3 Filesystem and Driver Consulting

“kedar” wrote in message news:xxxxx@ntdev…
> Hi,
>
> Here is the requirement once again. All you have to do is blank the local
> screen on which the piece of code is running. May be we can consider the
> situation if we want to block the user/employee from doing any action oh
his
> system.
>
> So this process talks to the display driver of the local machine and knows
> only the display controller ( may be the video memory ) of the local
machine
> and does not even know things like terminal clients talking to it.
>
> I thought we could achieve this by taking the Display card to a low power
> state. This can be generic since the Power Register in the PCI
configuration
> space can be used to drive the card to low power mode.
>
> Any other ideas?
>
> Regards,
> Kedar.
>
>
> “kedar” wrote in message news:xxxxx@ntdev…
> > Hi All,
> >
> > Is it possible to blank a monitor from driver code. The solution should
be
> > independent of the display adapter we use! Its something like what OS
does
> > to the screen on Hybernate/Standby.
> >
> > Any information is helpful.
> >
> > Regards,
> > Kedar
> >
> >
>
>
>

—
Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@encentrus.com
To unsubscribe send a blank email to xxxxx@lists.osr.com