Dispmanx: accessing a resource's native image memory


1 post
by Vanfanel » Sun Nov 04, 2012 3:53 pm
Hello there


In dispmanx, the function vc_dispmanx_resource_create seems to accept a parameter wich is called native_image_buffer, supposedly a handler for the native image buffer.
After some investigation it seems that this handler isn't useful to get a pointer to the actual base address of the physical pixel array (wich native_image_buffer seems to suggest), so I have to use the write_data function to indirectly copy data to that native buffer.

Now, if we look here:

viewtopic.php?f=67&t=20297

and here:

https://github.com/raspberrypi/firmware/issues/85

it's clear I am not the first person trying to access this precious memory area to save some valuable CPU time.

However, the only person who got this "holy grial" is hermanhermitage, so... Mr Herman, could you share some code on how you do it exactly?

What I did have success with was writing a signature to the surface, then scanning memory in /dev/mem


Thanks!
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