On Wed, Jul 29, 2015 at 05:23:44PM +0100, Michel Thierry wrote: > This clean-up version delays the 48-bit work to later patches and includes > more review comments from Akash and Chris. The first 5 patches prepare the > dynamic page allocation code to handle independent pdps, but no specific > code for 48-bit mode is added before the 5th patch. > > In order expand the GPU address space, a 4th level translation is added, > the Page Map Level 4 (PML4). This PML4 has 512 PML4 Entries (PML4E), > PML4[0-511], each pointing to a PDP. All the existing "dynamic alloc > ppgtt" functions are used, only adding the 4th level changes. I also > updated some remaining variables that were 32b only. > > There are 2 hardware workarounds needed to allow correct operation with > 48b addresses (Wa32bitGeneralStateOffset & Wa32bitInstructionBaseOffset). > A flag (EXEC_OBJECT_SUPPORTS_48B_ADDRESS) will indicate if a given object can > be allocated outside the first 4 PDPs; if not, the end range is forced to 4GB. > Also, more objects now use the DRM_MM_CREATE_TOP flag. To maintain > compatibility, in libdrm I added a new drm_intel_bo_emit_reloc_48bit function > that will flag these objects, while the existing drm_intel_bo_emit_reloc > clears it. > > Finally, this feature is only available in BDW and Gen9, requires LRC > submission mode (execlists) and it can be detected by i915.enable_ppgtt=3. > > Also note that this expanded address space is only available for full > PPGTT, aliasing PPGTT and Global GTT remain 32-bit. > > I'll resend the userland patches (libdrm/mesa) in a different patchset, there > haven't been changes on them, but they require a rebase. I will also expand the > ppgtt igt test per Chris suggestions. Just a head's up, I haven't root caused this yet, but with i915.enable_ppgtt=2 I started getting GPU hangs that didn't happen before this series... -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
