[PATCH v2 2/2] drm/amd/display: Move PRIMARY plane zpos higher
sunpeng.li at amd.com
sunpeng.li at amd.com
Mon Apr 29 19:48:05 UTC 2024
From: Leo Li <sunpeng.li at amd.com>
[Why]
Compositors have different ways of assigning surfaces to DRM planes for
render offloading. It may decide between various strategies: overlay,
underlay, or a mix of both (see here for more info:
https://gitlab.freedesktop.org/emersion/libliftoff/-/issues/76)
One way for compositors to implement the underlay strategy is to assign
a higher zpos to the DRM_PRIMARY plane than the DRM_OVERLAY planes,
effectively turning the DRM_OVERLAY plane into an underlay plane.
Today, amdgpu attaches an immutable zpos of 0 to the DRM_PRIMARY plane.
This however, is an arbitrary restriction. DCN pipes are general
purpose, and can be arranged in any z-order. To support compositors
using this allocation scheme, we can set a non-zero immutable zpos for
the PRIMARY, allowing the placement of OVERLAYS (mutable zpos range
0-254) beneath the PRIMARY.
[How]
Assign a zpos = #no of OVERLAY planes to the PRIMARY plane. Then, clean
up any assumptions in the driver of PRIMARY plane having the lowest
zpos.
Signed-off-by: Leo Li <sunpeng.li at amd.com>
Reviewed-by: Harry Wentland <harry.wentland at amd.com>
Acked-by: Pekka Paalanen <pekka.paalanen at collabora.com>
v2: Fix typo s/decending/descending/
---
.../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 34 +++++++++++++++++--
.../amd/display/amdgpu_dm/amdgpu_dm_plane.c | 18 +++++++---
2 files changed, 44 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index b4b5b73707c1..6782ca1137d4 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -80,6 +80,7 @@
#include <linux/firmware.h>
#include <linux/component.h>
#include <linux/dmi.h>
+#include <linux/sort.h>
#include <drm/display/drm_dp_mst_helper.h>
#include <drm/display/drm_hdmi_helper.h>
@@ -375,6 +376,20 @@ static inline void reverse_planes_order(struct dc_surface_update *array_of_surfa
swap(array_of_surface_update[i], array_of_surface_update[j]);
}
+/*
+ * DC will program planes with their z-order determined by their ordering
+ * in the dc_surface_updates array. This comparator is used to sort them
+ * by descending zpos.
+ */
+static int dm_plane_layer_index_cmp(const void *a, const void *b)
+{
+ const struct dc_surface_update *sa = (struct dc_surface_update *)a;
+ const struct dc_surface_update *sb = (struct dc_surface_update *)b;
+
+ /* Sort by descending dc_plane layer_index (i.e. normalized_zpos) */
+ return sb->surface->layer_index - sa->surface->layer_index;
+}
+
/**
* update_planes_and_stream_adapter() - Send planes to be updated in DC
*
@@ -399,7 +414,8 @@ static inline bool update_planes_and_stream_adapter(struct dc *dc,
struct dc_stream_update *stream_update,
struct dc_surface_update *array_of_surface_update)
{
- reverse_planes_order(array_of_surface_update, planes_count);
+ sort(array_of_surface_update, planes_count,
+ sizeof(*array_of_surface_update), dm_plane_layer_index_cmp, NULL);
/*
* Previous frame finished and HW is ready for optimization.
@@ -9503,6 +9519,8 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
for (j = 0; j < status->plane_count; j++)
dummy_updates[j].surface = status->plane_states[0];
+ sort(dummy_updates, status->plane_count,
+ sizeof(*dummy_updates), dm_plane_layer_index_cmp, NULL);
mutex_lock(&dm->dc_lock);
dc_update_planes_and_stream(dm->dc,
@@ -10237,6 +10255,16 @@ static bool should_reset_plane(struct drm_atomic_state *state,
if (new_crtc_state->color_mgmt_changed)
return true;
+ /*
+ * On zpos change, planes need to be reordered by removing and re-adding
+ * them one by one to the dc state, in order of descending zpos.
+ *
+ * TODO: We can likely skip bandwidth validation if the only thing that
+ * changed about the plane was it'z z-ordering.
+ */
+ if (new_crtc_state->zpos_changed)
+ return true;
+
if (drm_atomic_crtc_needs_modeset(new_crtc_state))
return true;
@@ -11076,7 +11104,7 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
}
/* Remove exiting planes if they are modified */
- for_each_oldnew_plane_in_state_reverse(state, plane, old_plane_state, new_plane_state, i) {
+ for_each_oldnew_plane_in_descending_zpos(state, plane, old_plane_state, new_plane_state) {
if (old_plane_state->fb && new_plane_state->fb &&
get_mem_type(old_plane_state->fb) !=
get_mem_type(new_plane_state->fb))
@@ -11121,7 +11149,7 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
}
/* Add new/modified planes */
- for_each_oldnew_plane_in_state_reverse(state, plane, old_plane_state, new_plane_state, i) {
+ for_each_oldnew_plane_in_descending_zpos(state, plane, old_plane_state, new_plane_state) {
ret = dm_update_plane_state(dc, state, plane,
old_plane_state,
new_plane_state,
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
index 3e467244ad07..bb534b2b0b71 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
@@ -104,8 +104,6 @@ void amdgpu_dm_plane_fill_blending_from_plane_state(const struct drm_plane_state
*global_alpha = false;
*global_alpha_value = 0xff;
- if (plane_state->plane->type == DRM_PLANE_TYPE_PRIMARY)
- return;
if (plane_state->pixel_blend_mode == DRM_MODE_BLEND_PREMULTI ||
plane_state->pixel_blend_mode == DRM_MODE_BLEND_COVERAGE) {
@@ -1701,6 +1699,7 @@ int amdgpu_dm_plane_init(struct amdgpu_display_manager *dm,
int res = -EPERM;
unsigned int supported_rotations;
uint64_t *modifiers = NULL;
+ unsigned int primary_zpos = dm->dc->caps.max_slave_planes;
num_formats = amdgpu_dm_plane_get_plane_formats(plane, plane_cap, formats,
ARRAY_SIZE(formats));
@@ -1730,10 +1729,19 @@ int amdgpu_dm_plane_init(struct amdgpu_display_manager *dm,
}
if (plane->type == DRM_PLANE_TYPE_PRIMARY) {
- drm_plane_create_zpos_immutable_property(plane, 0);
+ /*
+ * Allow OVERLAY planes to be used as underlays by assigning an
+ * immutable zpos = # of OVERLAY planes to the PRIMARY plane.
+ */
+ drm_plane_create_zpos_immutable_property(plane, primary_zpos);
} else if (plane->type == DRM_PLANE_TYPE_OVERLAY) {
- unsigned int zpos = 1 + drm_plane_index(plane);
- drm_plane_create_zpos_property(plane, zpos, 1, 254);
+ /*
+ * OVERLAY planes can be below or above the PRIMARY, but cannot
+ * be above the CURSOR plane.
+ */
+ unsigned int zpos = primary_zpos + 1 + drm_plane_index(plane);
+
+ drm_plane_create_zpos_property(plane, zpos, 0, 254);
} else if (plane->type == DRM_PLANE_TYPE_CURSOR) {
drm_plane_create_zpos_immutable_property(plane, 255);
}
--
2.44.0
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