diff options
Diffstat (limited to 'include/uapi/drm/i915_drm.h')
| -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. */ |