Looking for the simplest method to send some bytes from mirror display driver to application?

Hi all,

I have tried to compile and run the MS DDK sample mirror display driver. My
purpose is to get some bytes of data from the GDIINFO out to send to the
application.

I understand that the mirror display driver runs in kernel mode and my
application runs in user mode.

I want the mirror driver to either write to a file, or store the information
somewhere in the Windows memory. Then my application, upon lauching, can
query that information.

The information is only several bytes; and my application just needs to
query the information not very frequently, as long as the display hardware
does not change.

So is there any simple way of programming to get that information out of the
mirror driver?

Thanks a lot,

-Lucy

 

I think custom escape(s) is the way to go.

 

Hi Calvin,

Can I use global variable in mirror driver?

The information I want is in DrvEnablePDEV, but the DrvEscape is another
function, how can I transfer values?

Thanks a lot

 

Yes, you can.
-
Calvin Guan Software Engineer
ATI Technologies Inc. www.ati.com

 

Be careful with global variables in display (mirror) drivers!!! The will be
allocated in session space - not system-wide memory. This means that the
variables will only be available when the session is mapped. For your
application, this probably won't be a problem, but I've had students who have
run into this problem, when they try to access global variables that were
defined in a different session

-Brian

Brian Catlin, Sannas Consulting 310-944-9492
Windows Network, Video, WDM Device Driver Training & Consulting
See WWW.AZIUS.COM.bad for courses and scheduling
REMOVE .BAD FROM EMAIL AND WEB ADDRESS

 

Good point. I think at the point driver's DrvEscape got called by win32k,
the session space is valid.

Thanks,
Calvin
-
Calvin Guan Software Engineer
ATI Technologies Inc. www.ati.com

 

Sure, but if the variable was set during driver initialization, then it won't be

-Brian

Brian Catlin, Sannas Consulting 310-944-9492
Windows Network, Video, WDM Device Driver Training & Consulting
See WWW.AZIUS.COM.bad for courses and scheduling
REMOVE .BAD FROM EMAIL AND WEB ADDRESS

 

Ah, that's a big problem. Because I am exactly going to store some GDIINFO
information into this global variable during driver initialization... then
fetch it using DrvEscape function...

Is that the problem you've mentioned?

Thank you very much,

-Lucy