SYNOPSIS

int drm_gem_create_mmap_offset_size(struct drm_gem_object * obj, size_t size);

ARGUMENTS

obj

obj in question

size

the virtual size

DESCRIPTION

GEM memory mapping works by handing back to userspace a fake mmap offset it can use in a subsequent mmap(2) call. The DRM core code then looks up the object based on the offset and sets up the various memory mapping structures.

This routine allocates and attaches a fake offset for obj, in cases where the virtual size differs from the physical size (ie. obj->size). Otherwise just use drm_gem_create_mmap_offset.

This function is idempotent and handles an already allocated mmap offset transparently. Drivers do not need to check for this case.

AUTHORS

Jesse Barnes <[email protected]>
Intel Corporation,         
        

Initial version

Laurent Pinchart <[email protected]>
Ideas on board SPRL,         
        

Driver internals

Daniel Vetter <[email protected]>
Intel Corporation,         
        

Contributions all over the place

Lukas Wunner <[email protected]>

vga_switcheroo documentation

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