diff options
Diffstat (limited to 'include/uapi/drm')
| -rw-r--r-- | include/uapi/drm/i915_drm.h | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index 08d69e36fb66..2e613109356b 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -3346,8 +3346,33 @@ struct drm_i915_memory_region_info { /** @region: The class:instance pair encoding */ struct drm_i915_gem_memory_class_instance region; - /** @rsvd0: MBZ */ - __u32 rsvd0; + union { + /** @rsvd0: MBZ */ + __u32 rsvd0; + /** + * @gtt_alignment: + * + * The minimum required GTT alignment for this type of memory. + * When allocating a GTT address it must be aligned to this + * value or larger. On some platforms the kernel might opt to + * using 64K pages for I915_MEMORY_CLASS_DEVICE, where 64K GTT + * pages can then be used if we also use 64K GTT alignment. + * + * NOTE: If this is zero then this must be an older + * kernel which lacks support for this field. + * + * Side note: For larger objects (especially for + * I915_MEMORY_CLASS_DEVICE), like 2M+ in size, userspace should + * consider potentially bumping the GTT alignment to say 2M, + * which could potentially increase the likelihood of the kernel + * being able to utilise 2M GTT pages underneath, if the layout + * of the physical pages allows it. On some configurations we + * can then also use a more efficient page-table layout, if we + * can't use the more desirable 2M GTT page, so long as we know + * that the entire page-table will be used by this object. + */ + __u32 gtt_alignment; + }; /** * @probed_size: Memory probed by the driver |