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

Home NTDEV
Before Posting...
Please check out the Community Guidelines in the Announcements and Administration Category.

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/


Problem enabling MSI interrupts, invalid DeviceNode?

sandossandos Member Posts: 3

So I have been bashing my head against my inability to enable MSI interrupts for a PCI Express card for a few days now. In my IRP_MN_START_DEVICE handler where I connect my interrupts, if I enable MSI interrupts I get a "STATUS_NOT_SUPPORTED" back from IoConnectInterruptEx. If I debug a bit into the actual call I noticed that a null-check fails, and it turns out its the DeviceObject->DeviceObjectExtension->DeviceNode pointer which is null. This pointer is set in my AddDevice routine, at least it is not null. In all my IRP_MJ_PNP calls, it is now null.

I get a feeling that my device creation is wrong somehow. Does windows not think my driver needs a physical device node? I am using a custom device class if that matters. I only really found one pertinent Google hit and that was from a ReactOS developer suggesting this is a sanity check that fails. The post is titled "How to check for a valid PDO?".

Comments

  • Peter_Viscarola_(OSR)Peter_Viscarola_(OSR) Administrator Posts: 7,807

    Why are you writing a WDM driver, and not using WDF?

    Peter

    Peter Viscarola
    OSR
    @OSRDrivers

  • sandossandos Member Posts: 3
    edited May 13

    I had trouble with a very old windows 10 version apparently, and WDM worked but WDF did not. I think, possibly, that compiling for windows 8.1 instead solved the problem for me but at that point I had already switched over to WDM. Also the codebase I was using was WDM-based.

    Regarding the "Not supported" status, it seems to imply that the card does not support MSI interrupts! But alas, I can see with the pci windbg extension that both are enabled per the PCI flags. Also I get a list of resources in IRP_MN_FILTER_RESOURCE_REQUIREMENTS where I can see two MSI interrupt resources (with 4 and 1 messages) and one legacy. This all implies that MSI should work.

  • Shane_CorbinShane_Corbin Member Posts: 257

    What's your .inf look like?
    You know about this; right?

  • sandossandos Member Posts: 3

    @Shane_Corbin said:
    What's your .inf look like?
    You know about this; right?

    Yes. I can enable/disable MSI in the registry and I see different interrupt resources sent to me in both IRP_MN_FILTER_RESOURCE_REQUIREMENTS and IRP_MN_START_DEVICE. Also I see the MSI flag in the PCI configuration space change when I change the registry setting.

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!

Upcoming OSR Seminars
OSR has suspended in-person seminars due to the Covid-19 outbreak. But, don't miss your training! Attend via the internet instead!
Kernel Debugging 30 Mar 2020 OSR Seminar Space
Developing Minifilters 15 Jun 2020 LIVE ONLINE
Writing WDF Drivers 22 June 2020 LIVE ONLINE
Internals & Software Drivers 28 Sept 2020 Dulles, VA