[PATCH v17 7/8] drm/xe/display: Add support for AuxCCS

Tvrtko Ursulin
2026-01-28T10:14:00Z

Add support for mapping the auxiliary CCS buffer into the DPT page tables.

This will allow for better power efficiency by enabling the render
compression frame buffer modifiers such as
I915_FORMAT_MOD_Y_TILED_GEN12_RC_CCS in a following patch.

We do this by refactoring the code a bit so handling for the linear
auxiliary frame buffer can be added in a tidy way. Also replace some
hardcoded constants.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Cc: Michael J. Ruhl <michael.j.ruhl@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
---
drivers/gpu/drm/xe/display/xe_fb_pin.c | 111 ++++++++++++++++++-------
1 file changed, 81 insertions(+), 30 deletions(-)

diff --git a/drivers/gpu/drm/xe/display/xe_fb_pin.c b/drivers/gpu/drm/xe/display/xe_fb_pin.c
index b285cc446f57..7617c2b3f3cb 100644
--- a/drivers/gpu/drm/xe/display/xe_fb_pin.c
+++ b/drivers/gpu/drm/xe/display/xe_fb_pin.c
@@ -50,33 +50,94 @@ write_dpt_rotated(struct xe_bo *bo, struct iosys_map *map, u32 *dpt_ofs, u32 bo_
*dpt_ofs = ALIGN(*dpt_ofs, 4096);
}

+static unsigned int
+write_dpt_padding(struct iosys_map *map, unsigned int dest, unsigned int pad)
+{
+ /* The DE ignores the PTEs for the padding tiles */
+ return dest + pad * sizeof(u64);
+}
+
+static unsigned int
+write_dpt_remapped_linear(struct xe_bo *bo, struct iosys_map *map,
+ unsigned int dest,
+ const struct intel_remapped_plane_info *plane)
+{
+ struct xe_device *xe = xe_bo_device(bo);
+ struct xe_ggtt *ggtt = xe_device_get_root_tile(xe)->mem.ggtt;
+ const u64 pte = xe_ggtt_encode_pte_flags(ggtt, bo,
+ xe->pat.idx[XE_CACHE_NONE]);
+ unsigned int offset = plane->offset * XE_PAGE_SIZE;
+ unsigned int size = plane->size;
+
+ while (size--) {
+ u64 addr = xe_bo_addr(bo, offset, XE_PAGE_SIZE);
+
+ iosys_map_wr(map, dest, u64, addr | pte);
+ dest += sizeof(u64);
+ offset += XE_PAGE_SIZE;
+ }
+
+ return dest;
+}
+
+static unsigned int
+write_dpt_remapped_tiled(struct xe_bo *bo, struct iosys_map *map,
+ unsigned int dest,
+ const struct intel_remapped_plane_info *plane)
+{
+ struct xe_device *xe = xe_bo_device(bo);
+ struct xe_ggtt *ggtt = xe_device_get_root_tile(xe)->mem.ggtt;
+ const u64 pte = xe_ggtt_encode_pte_flags(ggtt, bo,
+ xe->pat.idx[XE_CACHE_NONE]);
+ unsigned int offset, column, row;
+
+ for (row = 0; row < plane->height; row++) {
+ offset = (plane->offset + plane->src_stride * row) *
+ XE_PAGE_SIZE;
+
+ for (column = 0; column < plane->width; column++) {
+ u64 addr = xe_bo_addr(bo, offset, XE_PAGE_SIZE);
+
+ iosys_map_wr(map, dest, u64, addr | pte);
+ dest += sizeof(u64);
+ offset += XE_PAGE_SIZE;
+ }
+
+ dest = write_dpt_padding(map, dest,
+ plane->dst_stride - plane->width);
+ }
+
+ return dest;
+}
+
static void
-write_dpt_remapped(struct xe_bo *bo, struct iosys_map *map, u32 *dpt_ofs,
- u32 bo_ofs, u32 width, u32 height, u32 src_stride,
- u32 dst_stride)
+write_dpt_remapped(struct xe_bo *bo,
+ const struct intel_remapped_info *remap_info,
+ struct iosys_map *map)
{
- struct xe_device *xe = xe_bo_device(bo);
- struct xe_ggtt *ggtt = xe_device_get_root_tile(xe)->mem.ggtt;
- u32 column, row;
- u64 pte = xe_ggtt_encode_pte_flags(ggtt, bo, xe->pat.idx[XE_CACHE_NONE]);
+ unsigned int i, dest = 0;

- for (row = 0; row < height; row++) {
- u32 src_idx = src_stride * row + bo_ofs;
+ for (i = 0; i < ARRAY_SIZE(remap_info->plane); i++) {
+ const struct intel_remapped_plane_info *plane =
+ &remap_info->plane[i];

- for (column = 0; column < width; column++) {
- u64 addr = xe_bo_addr(bo, src_idx * XE_PAGE_SIZE, XE_PAGE_SIZE);
- iosys_map_wr(map, *dpt_ofs, u64, pte | addr);
+ if (!plane->width && !plane->height && !plane->linear)
+ continue;

- *dpt_ofs += 8;
- src_idx++;
+ if (remap_info->plane_alignment) {
+ const unsigned int index = dest / sizeof(u64);
+ const unsigned int pad =
+ ALIGN(index, remap_info->plane_alignment) -
+ index;
+
+ dest = write_dpt_padding(map, dest, pad);
}

- /* The DE ignores the PTEs for the padding tiles */
- *dpt_ofs += (dst_stride - width) * 8;
+ if (plane->linear)
+ dest = write_dpt_remapped_linear(bo, map, dest, plane);
+ else
+ dest = write_dpt_remapped_tiled(bo, map, dest, plane);
}
-
- /* Align to next page */
- *dpt_ofs = ALIGN(*dpt_ofs, 4096);
}

static int __xe_pin_fb_vma_dpt(const struct intel_framebuffer *fb,
@@ -139,17 +200,7 @@ static int __xe_pin_fb_vma_dpt(const struct intel_framebuffer *fb,
iosys_map_wr(&dpt->vmap, x * 8, u64, pte | addr);
}
} else if (view->type == I915_GTT_VIEW_REMAPPED) {
- const struct intel_remapped_info *remap_info = &view->remapped;
- u32 i, dpt_ofs = 0;
-
- for (i = 0; i < ARRAY_SIZE(remap_info->plane); i++)
- write_dpt_remapped(bo, &dpt->vmap, &dpt_ofs,
- remap_info->plane[i].offset,
- remap_info->plane[i].width,
- remap_info->plane[i].height,
- remap_info->plane[i].src_stride,
- remap_info->plane[i].dst_stride);
-
+ write_dpt_remapped(bo, &view->remapped, &dpt->vmap);
} else {
const struct intel_rotation_info *rot_info = &view->rotated;
u32 i, dpt_ofs = 0;
--
2.52.0