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varunrajendran
Observer
Observer
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Registered: ‎04-06-2015

Zynq Linux issue with udev

Hi,

I am using "Linux zynq 3.10.0-xilinx". I did checkout of the tag Xilinx v14.7
I have cross compiled the kernel modules. I am using Zynq Z702 board, I have used the booting file for petalinux on Zynq from the below mentioned site.
http://www.wiki.xilinx.com/Zynq+14.7-2013.3+Release

 

I have created  a character kernel module and a user application communicating to the module using IOCTL.

 

I am able to communicate between the application for the first time but when I stop and restart the application the open returns error -1 (Unknown error -1).

 

After analyzing I noticed that after closing the application the devvice node for the driver in /dev missing for my kernel module. If i remove the module and reinsert it back the node is created again.
 
I have tested the same kernel module and user application on other Linux distribution (Ubuntu 14.04) and I don't see the same problem. The application can be restarted multiple times without any issue.

 

I also tested the application and driver with latest kernel version "Linux zynq 4.0.0-xilinx" but issue pervails.

 

I would like to know whether udev on Zynq will release the kernel module without doing rmmod when user application stops. Or is there any specific Linux settings which needs to be configured.

Regards,

Varun

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