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 at vmware.com> >> 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? Daniel, maybe you could elaborate a bit on this? Thomas > > Thierry > > > _______________________________________________ > dri-devel mailing list > dri-devel at lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/dri-devel
