FPGA Intellectual Property
PCI Express*, Networking and Connectivity, Memory Interfaces, DSP IP, and Video IP
Announcements
Intel Support hours are Monday-Fridays, 8am-5pm PST, except Holidays. Thanks to our community members who provide support during our down time or before we get to your questions. We appreciate you!

Need Forum Guidance? Click here
Search our FPGA Knowledge Articles here.
5953 Discussions

DeviceIOControl - DMA - Interrupt issues

Altera_Forum
Honored Contributor II
845 Views

Hi, 

 

Here is the logic flow: 

 

1. GUI program sends DeviceIoControl command setup to driver: 

setup DMA descriptors 

2. GUI program sends DeviceIoControl command Start to driver: 

call the routine of start DMA Read and write (with parameter of# of loops) 

3. ISR routine receives interrupts 

Checks# of loops, if not, zero, call the same of above routine to restart DMA R/W. 

 

It works only if put a debug line before start DMA: 

KdPrintf("."); //if this line is commented, no interrupts will be received.  

StartDMA(); 

 

Anyone has any suggestions what is wrong? 

Thanks, 

 

Tiger
0 Kudos
1 Reply
Altera_Forum
Honored Contributor II
114 Views

There are two problems: One it needs synchronization, and the other is to check the interrupt status registers, because the interrupt is shared by both read and write. That fixes the problem.

Reply