Op 06-12-12 22:50, Daniel Vetter schreef: > 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. > Yeah lets reinvent a new error to return, and make it not a typewriter to confuse users, instead of using -ENODEV which would actually be valid and most descriptive here if you read the mmap page: -ENODEV The underlying file system of the specified file does not support memory mapping. ~Maarten _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
