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| author |   Ramalingam C <ramalingam.c@intel.com> | 2022-05-02 19:45:08 +0530 |
|---|---|---|
| committer | Ramalingam C <ramalingam.c@intel.com> | 2022-05-18 14:34:38 +0530 |
| commit | a50794f26f52c66cb793d5d392f5f19bc2962cdd (patch) | |
| tree | 388ccf3c2a5ba5e3e3ee642e224384132ad931e7 /include/uapi/drm | |
| parent | drm/i915/guc: Remove unnecessary GuC err capture noise (diff) | |
| download | linux-dev-a50794f26f52c66cb793d5d392f5f19bc2962cdd.tar.xz linux-dev-a50794f26f52c66cb793d5d392f5f19bc2962cdd.zip | |
uapi/drm/i915: Document memory residency and Flat-CCS capability of obj
Capture the impact of memory region preference list of the objects, on
their memory residency and Flat-CCS capability.
v2:
Fix the Flat-CCS capability of an obj with {lmem, smem} preference
list [Thomas]
v3:
Reworded the doc [Matt]
v4:
Fixed Typos and spelling mistakes [Tvrtko, Joonas]
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
cc: Matthew Auld <matthew.auld@intel.com>
cc: Thomas Hellstrom <thomas.hellstrom@linux.intel.com>
cc: Daniel Vetter <daniel.vetter@ffwll.ch>
cc: Jon Bloomfield <jon.bloomfield@intel.com>
cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
cc: Kenneth Graunke <kenneth@whitecape.org>
cc: mesa-dev@lists.freedesktop.org
cc: Jordan Justen <jordan.l.justen@intel.com>
cc: Tony Ye <tony.ye@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Acked-by: Jordan Justen <jordan.l.justen@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220502141508.2327-1-ramalingam.c@intel.com
Diffstat (limited to 'include/uapi/drm')
| -rw-r--r-- | include/uapi/drm/i915_drm.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index a2def7b27009..de49b68b4fc8 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -3443,6 +3443,22 @@ struct drm_i915_gem_create_ext { * At which point we get the object handle in &drm_i915_gem_create_ext.handle, * along with the final object size in &drm_i915_gem_create_ext.size, which * should account for any rounding up, if required. + * + * Note that userspace has no means of knowing the current backing region + * for objects where @num_regions is larger than one. The kernel will only + * ensure that the priority order of the @regions array is honoured, either + * when initially placing the object, or when moving memory around due to + * memory pressure + * + * On Flat-CCS capable HW, compression is supported for the objects residing + * in I915_MEMORY_CLASS_DEVICE. When such objects (compressed) have other + * memory class in @regions and migrated (by i915, due to memory + * constraints) to the non I915_MEMORY_CLASS_DEVICE region, then i915 needs to + * decompress the content. But i915 doesn't have the required information to + * decompress the userspace compressed objects. + * + * So i915 supports Flat-CCS, on the objects which can reside only on + * I915_MEMORY_CLASS_DEVICE regions. */ struct drm_i915_gem_create_ext_memory_regions { /** @base: Extension link. See struct i915_user_extension. */ |