On Thu, Dec 06, 2012 at 10:46:30PM +0100, Daniel Vetter wrote: > On Thu, Dec 06, 2012 at 10:07:48AM -0800, Aaron Plattner wrote: > > Instead of reimplementing all of the dma_buf functionality in every driver, > > create helpers drm_prime_import and drm_prime_export that implement them in > > terms of new, lower-level hook functions: > > > > gem_prime_pin: callback when a buffer is created, used to pin buffers into GTT > > gem_prime_get_pages: convert a drm_gem_object to an sg_table for export > > gem_prime_import_sg: convert an sg_table into a drm_gem_object > > gem_prime_vmap, gem_prime_vunmap: map and unmap an object > > > > These hooks are optional; drivers can opt in by using drm_gem_prime_import and > > drm_gem_prime_export as the .gem_prime_import and .gem_prime_export fields of > > struct drm_driver. > > > > Signed-off-by: Aaron Plattner <aplattner@xxxxxxxxxx> > > A few comments: > > - Can you please add kerneldoc entries for these new helpers? Laurent > Pinchart started a nice drm kerneldoc as an overview. And since then > we've at least integrated the kerneldoc api reference at a nice place > there and brushed it up a bit when touching drm core or helpers in a > bigger patch series. See e.g. my recent dp helper series for what I'm > looking for. I think we should have kerneldoc at least for the exported > functions. > > - Just an idea for all the essential noop cpu helpers: Maybe just call > them dma_buf*noop and shovel them as convenience helpers into the > dma-buf.c code in the core, for drivers that don't want/can't/won't > bother to implement the cpu access support. Related: Exporting the > functions in general so that drivers could pick&choose One more: For the cpu access noop helpers I'd vote for -ENOTTY as the more canonical "not implemented error, you're talking to the wrong thing" error instead of -EINVAL, which an exporter could throw back to the importer if e.g. the range is outside of the size of the dma_buf. With a quick dma_buf doc update we could then bless this as the official way to denounce cpu access support. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
