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


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:

Before Posting...

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

Status timeout from umdf virtualserial port

goodfriendgoodfriend Member Posts: 5

I am working on VirtualSerial at the following link.

This sample working good as expected with reading & writing through serial port applications.

How can I response STATUS_TIMEOUT to IRP_MJ_READ request when there is no reading data ?

Using standart usb serial port devices response STATUS_TIMEOUT, but virtualserial can not.
I tried following options , but it is not STATUS_TIMEOUT response.

        // No data to read. Queue the request for later processing.
        //pSavedRequest->CompleteWithInformation(E_FAIL, STATUS_TIMEOUT);
        //pSavedRequest->CompleteWithInformation(STATUS_TIMEOUT, 0);

I find out WdfTimerCreate function to handle this issue, but i do not know how can fix for virtual serial.

In sampe repository, in Serial device project , there is some code part about creating timers to current read complete as following :


Routine Description:

   This function creates all the timers and DPC objects. All the objects
   are associated with the WDFDEVICE and the callbacks are serialized
   with the device callbacks. Also these objects will be deleted automatically
   when the device is deleted, so there is no need for the driver to explicitly
   delete the objects.


   PDevExt - Pointer to the device extension for the device

Return Value:

    return NTSTATUS

   WDF_DPC_CONFIG dpcConfig;
   WDF_TIMER_CONFIG timerConfig;
   NTSTATUS status;
   WDF_OBJECT_ATTRIBUTES timerAttributes;

   // Initialize all the timers used to timeout operations.
   // This timer dpc is fired off if the timer for the total timeout
   // for the read expires.  It will cause the current read to complete.

   WDF_TIMER_CONFIG_INIT(&timerConfig, SerialReadTimeout);

   timerConfig.AutomaticSerialization = TRUE;

   timerAttributes.ParentObject = pDevExt->WdfDevice;

   status = WdfTimerCreate(&timerConfig,


  • Tim_RobertsTim_Roberts Member - All Emails Posts: 13,909
    edited April 5

    The question confuses me. If you have a request, and you want it to fail with a timeout error, you do pSavedRequest->Complete(STATUS_TIMEOUT); Serial drivers usually have to check their saved settings to see whether they should fail an empty read request immediately, or wait for a timer to expire, but the method of failing the request is the same. The second snipped you showed is for KMDF or UMDF v2; that's not how you do a timer with UMDF v1.

    Tim Roberts, [email protected]
    Providenza & Boekelheide, Inc.

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!
Developing Minifilters 24 May 2021 Live, Online
Writing WDF Drivers 14 June 2021 Live, Online
Internals & Software Drivers 2 August 2021 Live, Online
Kernel Debugging 27 Sept 2021 Live, Online