Hi, All. I am about to merge the drm-ttm-0-2 branch into git master. It's a fair amount of code and to summarize added features:
1) Support for generic user-space objects / refcounting and removal on client exit. If you have a kernel object and want to make it visible to one or more user-space processes using a 32-bit hashed handle, this is very useful. 2) ttms, Translation table maps. These are like shared-memory maps with on-demand-allocated physical pages that can be flipped in and out of a GART/GATT/GTT, with all caching and mapping operations taken care of. User space transparently accesses the memory through a single virtual mapping regardless of where the memory is currently located. Full AGP flipping is unfortunately somewhat slow due to TLB flushing operations, but this might be improved in the future. The ttm functionality requires a modified AGP driver. It can be found at git://anongit.freedesktop.org/git/mesa/linux-agp-compat 3) Fence objects. A somewhat generic fence object implementation built on top of the user-space object implementation with a driver for intel hardware. Fence objects are used for GPU command stream synchronization and to signal GPU command completion. 4) Buffer objects built on top of the object / TTM / memory manager implementation with a driver for intel hardware. There have been attempts to move more of the functionality to user space (the drm-ttm-0-1-branch) but in the end the overhead of an IOCTL here and there was not really noticeable, so these efforts were discointinued. The current speed bottleneck is that allocating an AGP buffer requires flipping of a number of pages into the AGP aperture and a TLB flush, which is slow. Thus the buffer object manager should typically be used to allocate memory chunks that in turn can be managed in user space using a simple memory manager that can always assume the memory is present and it's content never lost. Currently only AGP functionality is implemented. VRAM is not functional yet. Caveats: a) libdrm now requires support for 64-bit file offsets, since mapping of buffer objects uses 64-bit file-handles, even on 32-bit hardware. b) Some changes have been made to the drm locking mechanism that greatly improves scheduling of multiple DRI clients, that could previously be starved. The DRM will also complain about locking / unlocking errors that were masked by the previous implementation. In particular when a client unlocks another client's lock. This comes with a small overhead: Clients that obtained the lock using a kernel call will always return to the kernel to unlock. Otherwise the DRM should be fully backwards compatible. If anybody sees a problem with the merge, please let me know ASAP. /Thomas ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
