I want to use inverted model of ioctl. I mean I want to schedule some work item which is a user space thread when a particular activity is detected by the driver. For eg.
1. I register a callback for a particular interrupt in my kernel mode driver.
2. Whenever I get an interrupt, I want to schedule some user space thread which user had registered using ioctl.
Can I use either DPC, APC or IRP to do so. I do know that one should not/cant differ driver space work to user space. What I want is to do some independent activities in the user space when a particular hardware event happens.
Thanks
creating usermode threads from driver is really bad practice and you can`t simple transfer control from kernel mode to user mode. You must create worker threads in user app and wait in this threads for event. There are two main approaches for waiting. 1) You can wait on some event, witch you post to driver in ioctl. In some moment driver set event to alertable and thread go and process event. This is major and simple approach
2) You can post ioctl synchronously and in driver pend this irp -> thread blocks in DeviceIoControl call. When event occured driver complete these irp and thread wake up and go for processing.
Whenever I get an interrupt, I want to schedule some user space threads which user had registered using ioctl.
You must go to safe irql (< DISPATCH_IRQL) first : Interrupt -> DPC push into queue -> worker thread, because for example you can`t signal event on high irql.
read this http://www.osronline.com/article.cfm?id=108
and Walter Oney book