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Diffstat (limited to 'Documentation/gpu/drm-mm.rst')
| -rw-r--r-- | Documentation/gpu/drm-mm.rst | 40 |
1 files changed, 4 insertions, 36 deletions
diff --git a/Documentation/gpu/drm-mm.rst b/Documentation/gpu/drm-mm.rst index c8ebd4f66a6a..b664f054c259 100644 --- a/Documentation/gpu/drm-mm.rst +++ b/Documentation/gpu/drm-mm.rst @@ -433,43 +433,11 @@ PRIME is the cross device buffer sharing framework in drm, originally created for the OPTIMUS range of multi-gpu platforms. To userspace PRIME buffers are dma-buf based file descriptors. -Overview and Driver Interface ------------------------------ +Overview and Lifetime Rules +--------------------------- -Similar to GEM global names, PRIME file descriptors are also used to -share buffer objects across processes. They offer additional security: -as file descriptors must be explicitly sent over UNIX domain sockets to -be shared between applications, they can't be guessed like the globally -unique GEM names. - -Drivers that support the PRIME API must set the DRIVER_PRIME bit in the -struct :c:type:`struct drm_driver <drm_driver>` -driver_features field, and implement the prime_handle_to_fd and -prime_fd_to_handle operations. - -int (\*prime_handle_to_fd)(struct drm_device \*dev, struct drm_file -\*file_priv, uint32_t handle, uint32_t flags, int \*prime_fd); int -(\*prime_fd_to_handle)(struct drm_device \*dev, struct drm_file -\*file_priv, int prime_fd, uint32_t \*handle); Those two operations -convert a handle to a PRIME file descriptor and vice versa. Drivers must -use the kernel dma-buf buffer sharing framework to manage the PRIME file -descriptors. Similar to the mode setting API PRIME is agnostic to the -underlying buffer object manager, as long as handles are 32bit unsigned -integers. - -While non-GEM drivers must implement the operations themselves, GEM -drivers must use the :c:func:`drm_gem_prime_handle_to_fd()` and -:c:func:`drm_gem_prime_fd_to_handle()` helper functions. Those -helpers rely on the driver gem_prime_export and gem_prime_import -operations to create a dma-buf instance from a GEM object (dma-buf -exporter role) and to create a GEM object from a dma-buf instance -(dma-buf importer role). - -struct dma_buf \* (\*gem_prime_export)(struct drm_device \*dev, -struct drm_gem_object \*obj, int flags); struct drm_gem_object \* -(\*gem_prime_import)(struct drm_device \*dev, struct dma_buf -\*dma_buf); These two operations are mandatory for GEM drivers that -support PRIME. +.. kernel-doc:: drivers/gpu/drm/drm_prime.c + :doc: overview and lifetime rules PRIME Helper Functions ---------------------- |