Neon code hangs

DRIVERHACKER

Other Parts Discussed in Thread: OMAP3503

Hello Everybody, I have observed that neon code hangs on mistral board. I have hand optimized my codec for neon. My application(without neon optimization) runs indefinitly without any problem. But in case of neon optimized code, my application hangs after I run my decoder/encoder in a while(1) loop. Sometimes this happens in 5 mins and sometimes after half an hour. Did I miss anything while running my neon optimized application on board. I am using init_cpu() on simulator which initialized processor for neon/fpu. Do I need any suchthing on hardware. I was of opinion that Kernel will initialized board for neon/vfu. Did anyone faced such a problem earlier. Thanks!

over 16 years ago

Juan Gonzales over 16 years ago

TI__Mastermind 37340 points

If you are configuring the Linux kernel for OMAP3503, NEON is disabled by default. See the following wiki post on how to enable NEON in the kernel

http://tiexpressdsp.com/wiki/index.php?title=FAQ_OMAP35x_Linux_PSP

Also, please make sure you are using Code Sourcery 2007 Q3 toolchain.

DRIVERHACKER over 16 years ago in reply to Juan Gonzales

Intellectual 310 points

I know that if neon support in kernel is not enabled, we should recieve ILLEGAL INSTRUCTION message. I have enabled neon in latest kernel 1.0. My problem is board hangs completly and even ctr-c does not work. I have to restart the board again. This problem occurs random (after say 1-30 min).

Bernie Thompson TI over 16 years ago in reply to DRIVERHACKER

TI__Mastermind 41665 points

How much neon code did you add in to your codec? Was there a particular neon instruction that you added that is causing this failuire? As far as I know there are no outright issues with running neon code, you may want to revert your code back to non neon and try adding in pieces of neon code a bit at a time, if you find that only a particular instruction fails, or only a particular portion of code than it may point you in the right direction to solving the issue.

Arno Steffens over 15 years ago in reply to Bernie Thompson TI

Intellectual 930 points

I do have trouble with NEON too. It is running but 4 times slower than it should be. (reffering to a TI benchmark)

I found that it depends on kernel AND uboot. So with the old 22 kernel it works fine and fast, the newer 29 kernel needs also the new uboot to be almost as fast as the 22.

So I assume that kernel is not configuring the NEON in a good way - otherwise it shoudn't be dependend on the bootloader! This is what I would call a bug.

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Neon code hangs