Windows System Software -- Consulting, Training, Development -- Unique Expertise, Guaranteed Results

Home NTDEV

More Info on Driver Writing and Debugging


The free OSR Learning Library has more than 50 articles on a wide variety of topics about writing and debugging device drivers and Minifilters. From introductory level to advanced. All the articles have been recently reviewed and updated, and are written using the clear and definitive style you've come to expect from OSR over the years.


Check out The OSR Learning Library at: https://www.osr.com/osr-learning-library/


Before Posting...

Please check out the Community Guidelines in the Announcements and Administration Category.

Possible causes of STATUS_DEVICE_POWER_FAILURE for a virtual display adapter?

2»

Comments

  • scott_smithscott_smith Member Posts: 81
    edited April 25

    just one hint: If you finally listen to my advice, then you can proceed without even worrying about this

    I've dragged my feet on this for a few reasons. I didn't assume that your example SDDL could be copied verbatim into my .inf file (sounds like you're suggesting that it can, though). I don't yet know enough to confidently compose my own. Also, I wanted to pursue this far enough to feel assured that assigning a security descriptor in the INF file (vs. using the default) wouldn't just be masking the root problem.


    Scott Smith
    Windows Developer since 1989

  • scott_smithscott_smith Member Posts: 81

    Noticed today that each time I disable/enable the adapter, it toggles between returning Access Denied and succeeding.

    I.e., it goes from working back to not working if I toggle the enabled state. Then it goes from not working back to working when I toggle it again...


    Scott Smith
    Windows Developer since 1989

  • Marcel_RuedingerMarcel_Ruedinger Member Posts: 168
    edited April 25

    Why "sounds like"? Was there anything wrong or difficult to understand?

    PS: Always glad to improve my foreign language skills in English if possible ;-)

    Marcel Ruedinger
    datronicsoft

  • scott_smithscott_smith Member Posts: 81
    edited April 25

    I didn't assume that your example SDDL could be copied verbatim into my .inf file (sounds like you're suggesting that it can, though)

    Why "sounds like"? Was there anything wrong or difficult to understand?

    Not at all. Your English is so perfect, I forgot that it's not your native language. :-)

    Ever tried to assign a security descriptor in the INF file (see example below)?

    From the word example above, it wasn't clear that the implication was to use the provided string verbatim. I'll go ahead and do that and report back shortly.


    Scott Smith
    Windows Developer since 1989

  • Marcel_RuedingerMarcel_Ruedinger Member Posts: 168
    edited April 25

    Yes, I observed the same funny behavior (and probably even more than that).
    The whole thing is probably specific to the Setup Class Display.
    I vaguely remember that I might have experienced similar effects decades ago with Windows XP when I wrote a Filter Driver for \Device\VideoX and DosDevices\DisplayY. I will try to find out what this is all about...

    Short status summary to touch base again with 100% mutual understanding:
    I initially gave you this security descriptor only because your application was my primary suspect. I considered (and still do) that this was the most effective approach at that time. It would have either pointed at your application or ruled it out immediately. Now that you ruled it out the hard way, the security descriptor has probably become the only remaining option to get something up and running at all.

    BTW: Two of our messages above must have crossed. My reply obviously has missed one post of yours.

    Marcel Ruedinger
    datronicsoft

    Post edited by Marcel_Ruedinger on
  • scott_smithscott_smith Member Posts: 81

    Marcel, et. al.,

    I added the HKR,, Security,, "D:P(A;;GA;;;SY)(A;;GA;;;BA)(A;;GA;;;WD)(A;;GA;;;RC)" line to my .inf file and the problem disappeared. It doesn't occur after driver install or Windows restart.

    Thanks for your help with this!


    Scott Smith
    Windows Developer since 1989

  • Marcel_RuedingerMarcel_Ruedinger Member Posts: 168

    Wait - we are not done yet! Who was the one who didn't want to take this security descriptor verbatim? ;-)

    We still have to ask one fundamental question here: Do you want to require admin privileges for your application to access the IddCx driver upper edge IOCTL interface? In that case, the above security descriptor is not good!

    It might actualy make very good sense to require admin privileges for the API here in this case. You might already have noticed that your application needs admin privileges anyway, right? This is due to SwDeviceCreate(...).

    Marcel Ruedinger
    datronicsoft

  • scott_smithscott_smith Member Posts: 81

    Do you want to require admin privileges for your application to access the IddCx driver upper edge IOCTL interface?

    Yes, definitely.

    I haven't done it yet, but I was planning to go through the SDS you gave me and make sure I understood what it was doing.


    Scott Smith
    Windows Developer since 1989

Sign In or Register to comment.

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!