Kernel outputting CL_UNKNOWN_ERROR

Kernel outputting CL_UNKNOWN_ERROR - Printable Version

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Kernel outputting CL_UNKNOWN_ERROR - lehrling - 06-18-2018

Hello, Im developing a mode for an old file format. At some point in my code, I do something like;

Code:
__kernel function1() {

     struct mytype;

     function2(&mytype);

}

function2(struct *mytype) {

     uchar *ptr = mytype->value2;

     function3(ptr);

}

function3(byte* ptr) {

     uint16 v1 = 10;

     uint16* ptr2 = (uint16*) ptr;

     *ptr2 = v1 >> 8; 

}

struct mytype {

      uchar value1[8];

      uchar value2[8];

      uint key[52];

      uint bufleft;

 }

This code fails at

Code:
*ptr2 = v1 >> 8;

with clWaitForEvents(): CL_UNKNOWN_ERROR. If I remove this single assignment, the code runs without errors. Does anybody has any tip on how to solve this problem?

RE: Kernel outputting CL_UNKNOWN_ERROR - atom - 06-19-2018

From a C perspective it's fine (if we assumbe byte* is some 8 bit datatype), but in OpenCL everything is different. What I mean is that you have to find workarounds that do the same you try to do but are more easy for the compiler to understand.

Try could try to use uchar* instead in the function declaration. But it's more likely that you can not make use of 8 bit datatypes, since they do not exist natively on a GPU. There's on 32 bit registers and that's it. So for example you can use a combination out of div and mod and switch() in order to emulate what you do with the cast. Anyway, welcome to my world Smile

RE: Kernel outputting CL_UNKNOWN_ERROR - lehrling - 06-26-2018

(06-19-2018, 09:47 AM)atom Wrote: From a C perspective it's fine (if we assumbe byte* is some 8 bit datatype), but in OpenCL everything is different. What I mean is that you have to find workarounds that do the same you try to do but are more easy for the compiler to understand.

Try could try to use uchar* instead in the function declaration. But it's more likely that you can not make use of 8 bit datatypes, since they do not exist natively on a GPU. There's on 32 bit registers and that's it. So for example you can use a combination out of div and mod and switch() in order to emulate what you do with the cast. Anyway, welcome to my world

Thanks for the tips atom. I'll try to rewrite it. The code behavior is still not making much sense, but I'll try your sugestions.

RE: Kernel outputting CL_UNKNOWN_ERROR - lehrling - 06-26-2018

Problem solved. I just changed my code from using the aligned data types to the unaligned data types, eg, u8a to u8.