[FFmpeg-devel] [PATCH 08/14] hwcontext_opencl: DRM to OpenCL mapping for ARM

[Mark Thompson]

On 19/09/17 20:24, wm4 wrote:
> On Sun, 10 Sep 2017 21:53:32 +0100
> Mark Thompson <sw at jkqxz.net> wrote:
> 
>> Using cl_arm_import_memory.  Unfortunately, despite this not being a
>> standard extension, the function clImportMemoryARM() is not accessible
>> via clGetExtensionFunctionAddressForPlatform().  This means that it has
>> to be linked directly to the ARM OpenCL binary, so making a portable
>> binary is not possible as it is with all other mapping extensions.
>> ---
> 
> So, just what does this have to do with ARM? (Basically asking for some
> background here how this came to be.)

Think ARM the company, not ARM the architecture.  It's a vendor extension for OpenCL made by ARM - <https://www.khronos.org/registry/OpenCL/extensions/arm/cl_arm_import_memory.txt>.  They implement it in their drivers for Mali GPUs: I have it doing interop with the Rockchip decoder (using the recent patches for that here on the ML).

- Mark