Problems enabling hps2fpga & lwhps2fpga bridges

[Altera_Forum]

the problem:When trying to enable either the hps2fpga or the lwhps2fpga bridge in Linux, the Linux system locks up. 

 From the rocketboards example: Command used: "echo 1 > /sys/class/fpga-bridge/hps2fpga/enable" *or* Command used: "echo 1 > /sys/class/fpga-bridge/lwhps2fpga/enable"   other useful information: -The FPGA is configured with a validated .rbf (and indicates in "user mode" per /sys/class/fpga/fpga0/status) -The fpga2hps bridge can be enabled/disabled normally. -The issue has appeared after we switched Linux versions and the configurator from Yocto to Buildroot -If the FPGA is configured with the .rbf and a reboot command issued, the bridges are up once Linux boots and our system functions normally. *unless we try to bring down the hps2fpga/lwhps2fpga bridges   The issue in question has appeared since we switched our Linux environment. There is a high probability that we have missed a configuration setting that would be needed to properly perform this action - any suggestions on this front would be highly welcome.  Not sure if it is helpful or not, the version from /etc/os-release indicates 2015.08-git.  Thank you in advance for any assistance.     

[Altera_Forum]

Another day of troubleshooting and the problem has been fixed. 

 Once we re-generated the .dtb for the core system, everything started working normally again. I can't say specifically what was wrong with the previous one, but the guess is that our implementer utilized a .dtb packaged with a GHRD and did not generate it from our actual system. I hope this helps anyone with a similar problem.  -Kosh271

[Altera_Forum]

Hi there, I will ask you a couple of questions just to double check and clarify my understanding of your problem: 

 Your post lets me to think you are using an example/reference design. If you are, can you specify which example are you using?  Where you trying this by using a modified FPGA system? eg: where you using a compiled rbf of your own with modifications with respect to the GHRD?  After you re-generated your dtb, did you have to re-compile any parts of your software? FSBL, kernel?  Many thanks in advance!

[Altera_Forum]

Hi! have you got a solution? Thanks. 

--- Quote Start ---  Another day of troubleshooting and the problem has been fixed.  Once we re-generated the .dtb for the core system, everything started working normally again. I can't say specifically what was wrong with the previous one, but the guess is that our implementer utilized a .dtb packaged with a GHRD and did not generate it from our actual system. I hope this helps anyone with a similar problem.  -Kosh271  --- Quote End ---