On Wed, 2022-03-02 at 03:23 +0530, Ramalingam C wrote:
> On Xe-HP and later devices, we use dedicated compression control
> state (CCS) stored in local memory for each surface, to support the
> 3D and media compression formats.
>
> The memory required for the CCS of the entire local memory is 1/256
> of
> the local memory size. So before the kernel boot, the required memory
> is reserved for the CCS data and a secure register will be programmed
> with the CCS base address
>
> So when we allocate a object in local memory we dont need to
> explicitly
> allocate the space for ccs data. But when we evict the obj into the
> smem to hold the compression related data along with the obj we need
> smem space of obj_size + (obj_size/256).
>
> Hence when we create smem for an obj with lmem placement possibility
> we
> create with the extra space.
Nit: Again imperative wording,
>
> Signed-off-by: Ramalingam C <ramalingam.c@xxxxxxxxx>
> cc: Christian Koenig <christian.koenig@xxxxxxx>
> cc: Hellstrom Thomas <thomas.hellstrom@xxxxxxxxx>
Reviewed by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 23 ++++++++++++++++++++++-
> 1 file changed, 22 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> index 1a8262f5f692..c7a36861c38d 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> @@ -20,6 +20,7 @@
> #include "gem/i915_gem_ttm.h"
> #include "gem/i915_gem_ttm_move.h"
> #include "gem/i915_gem_ttm_pm.h"
> +#include "gt/intel_gpu_commands.h"
>
> #define I915_TTM_PRIO_PURGE 0
> #define I915_TTM_PRIO_NO_PAGES 1
> @@ -255,12 +256,27 @@ static const struct i915_refct_sgt_ops
> tt_rsgt_ops = {
> .release = i915_ttm_tt_release
> };
>
> +static inline bool
> +i915_gem_object_has_lmem_placement(struct drm_i915_gem_object *obj)
> +{
> + int i;
> +
> + for (i = 0; i < obj->mm.n_placements; i++)
> + if (obj->mm.placements[i]->type ==
> INTEL_MEMORY_LOCAL)
> + return true;
> +
> + return false;
> +}
> +
> static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object
> *bo,
> uint32_t page_flags)
> {
> + struct drm_i915_private *i915 = container_of(bo->bdev,
> typeof(*i915),
> + bdev);
> struct ttm_resource_manager *man =
> ttm_manager_type(bo->bdev, bo->resource->mem_type);
> struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
> + unsigned long ccs_pages = 0;
> enum ttm_caching caching;
> struct i915_ttm_tt *i915_tt;
> int ret;
> @@ -283,7 +299,12 @@ static struct ttm_tt *i915_ttm_tt_create(struct
> ttm_buffer_object *bo,
> i915_tt->is_shmem = true;
> }
>
> - ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags, caching, 0);
> + if (HAS_FLAT_CCS(i915) &&
> i915_gem_object_has_lmem_placement(obj))
> + ccs_pages = DIV_ROUND_UP(DIV_ROUND_UP(bo->base.size,
> +
> NUM_BYTES_PER_CCS_BYTE),
> + PAGE_SIZE);
> +
> + ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags, caching,
> ccs_pages);
> if (ret)
> goto err_free;
>
