Hi Noralf,
On 23 July 2017 at 20:16, Noralf Trønnes noralf@tronnes.org wrote:
Add a common drm_driver.dumb_map_offset function for GEM backed drivers.
Signed-off-by: Noralf Trønnes noralf@tronnes.org
drivers/gpu/drm/drm_gem.c | 35 +++++++++++++++++++++++++++++++++++ include/drm/drm_gem.h | 2 ++ 2 files changed, 37 insertions(+)
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index 5df028a..a8d396b 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -311,6 +311,41 @@ drm_gem_handle_delete(struct drm_file *filp, u32 handle) EXPORT_SYMBOL(drm_gem_handle_delete);
/**
- drm_gem_dumb_map_offset - return the fake mmap offset for a gem object
- @file: drm file-private structure containing the gem object
- @dev: corresponding drm_device
- @handle: gem object handle
- @offset: return location for the fake mmap offset
- This implements the &drm_driver.dumb_map_offset kms driver callback for
- drivers which use gem to manage their backing storage.
- Returns:
- 0 on success or a negative error code on failure.
- */
+int drm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
u32 handle, u64 *offset)+{
struct drm_gem_object *obj;int ret;obj = drm_gem_object_lookup(file, handle);if (!obj)return -ENOENT;ret = drm_gem_create_mmap_offset(obj);
With later patches one goes to reuse this helper instead of drm_gem_cma_dumb_map_offset(). At the same time, the latter does not have the drm_gem_create_mmap_offset() call we see here.
Meanwhile some drivers have their own offset function which is virtually identical to the original drm_gem_cma_dumb_map_offset. Yet those are left unchanged.
For example in cirrus [1]: There the only code difference seems to be an "upcast" followed immediately by a "downcast". Which should effectively be a noop.
That said, I could be loosing my marbles.
HTH Emil
[1] https://cgit.freedesktop.org/drm/drm-misc/tree/drivers/gpu/drm/cirrus/cirrus...