On Sat, Dec 14, 2013 at 7:47 AM, Thomas Hellstrom <thomas@xxxxxxxxxxxx> wrote: > On 12/14/2013 01:37 PM, Thierry Reding wrote: >> >> On Thu, Dec 12, 2013 at 11:30:23PM +0100, Daniel Vetter wrote: >>> >>> On Thu, Dec 12, 2013 at 8:34 PM, Thomas Hellstrom <thellstrom@xxxxxxxxxx> >>> wrote: >>>> >>>> On 12/12/2013 03:36 PM, Thierry Reding wrote: >>>>> >>>>> This is a simple test module that can be used to allocate, export and >>>>> delete DMA-BUF objects. It can be used to test DMA-BUF sharing in >>>>> systems that lack a real second driver. >>>>> >>>>> >>>> Looks nice. I wonder whether this could be extended to create a >>>> "streaming" >>>> dma-buf from a user space mapping. That could be used as a generic way >>>> to >>>> implement streaming (user) buffer objects, rather than to add explicit >>>> support for those in, for example, TTM. >>> >>> Atm there's no way to get gpus to unbind their dma-buf mappings, so >>> their essentially pinned forever from first use on. >> >> Shouldn't this work by simply calling the GEM_CLOSE IOCTL on the handle >> returned by drmPrimeFDToHandle()? I mean that should drop the last >> reference on the GEM object and cause it to be cleaned up (which should >> include detaching the DMA-BUF). > > > Actually, while the GEM prime implementation appears to pin an exported > dma-buf on first attach, from the dma-buf documentation it seems sufficient > to pin it on map or cpu access. > > But what I assume Daniel is referring to is that there is no way for > exporters to tell importers to force unmap() the dma-buf, so that it can be > unpinned? yeah, or some way for importers to opportunistically keep around a mapping rather than map/unmap on each use.. maybe we need something shrinker-ish for dmabuf? BR, -R > Daniel, maybe you could elaborate a bit on this? > > Thomas > >> >> Thierry >> >> >> >> _______________________________________________ >> dri-devel mailing list >> dri-devel@xxxxxxxxxxxxxxxxxxxxx >> http://lists.freedesktop.org/mailman/listinfo/dri-devel > > > > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/dri-devel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
