From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
The cursor hardware only does sync updates, and thus the hardware
will be scanning out from the old fb until the next start of vblank.
So in order to make the legacy cursor fastpath actually safe we
should not unpin the old fb until we're sure the hardware has
ceased accessing it. The simplest approach is to just use a vblank
work here to do the delayed unpin.
Not 100% sure it's a good idea to put this onto the same high
priority vblank worker as eg. our timing critical gamma updates.
But let's keep it simple for now, and it we later discover that
this is causing problems we can think about adding a lower
priority worker for such things.
This patch is slightly reworked by Maarten
Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_cursor.c | 37 ++++++++++++++++---
drivers/gpu/drm/i915/display/intel_display.c | 3 ++
.../drm/i915/display/intel_display_types.h | 3 ++
3 files changed, 38 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_cursor.c b/drivers/gpu/drm/i915/display/intel_cursor.c
index b342fad180ca5..1728ecd5cc782 100644
--- a/drivers/gpu/drm/i915/display/intel_cursor.c
+++ b/drivers/gpu/drm/i915/display/intel_cursor.c
@@ -603,6 +603,17 @@ static bool intel_cursor_format_mod_supported(struct drm_plane *_plane,
return format == DRM_FORMAT_ARGB8888;
}
+static void intel_cursor_unpin_work(struct kthread_work *base)
+{
+ struct drm_vblank_work *work = to_drm_vblank_work(base);
+ struct intel_plane_state *plane_state =
+ container_of(work, typeof(*plane_state), unpin_work);
+ struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);
+
+ intel_plane_unpin_fb(plane_state);
+ intel_plane_destroy_state(&plane->base, &plane_state->uapi);
+}
+
static int
intel_legacy_cursor_update(struct drm_plane *_plane,
struct drm_crtc *_crtc,
@@ -688,9 +699,14 @@ intel_legacy_cursor_update(struct drm_plane *_plane,
if (ret)
goto out_free;
- ret = intel_plane_pin_fb(new_plane_state);
- if (ret)
- goto out_free;
+ if (new_plane_state->uapi.fb != old_plane_state->uapi.fb) {
+ ret = intel_plane_pin_fb(new_plane_state);
+ if (ret)
+ goto out_free;
+ } else {
+ /* magic trick */
+ swap(new_plane_state->ggtt_vma, old_plane_state->ggtt_vma);
+ }
intel_frontbuffer_flush(to_intel_frontbuffer(new_plane_state->hw.fb),
ORIGIN_CURSOR_UPDATE);
@@ -730,14 +746,25 @@ intel_legacy_cursor_update(struct drm_plane *_plane,
local_irq_enable();
- intel_plane_unpin_fb(old_plane_state);
+ if (old_plane_state->uapi.fb != new_plane_state->uapi.fb) {
+ drm_vblank_work_init(&old_plane_state->unpin_work, &crtc->base,
+ intel_cursor_unpin_work);
+
+ drm_vblank_work_schedule(&old_plane_state->unpin_work,
+ drm_crtc_accurate_vblank_count(&crtc->base) + 1,
+ false);
+
+ old_plane_state = NULL;
+ } else {
+ intel_plane_unpin_fb(old_plane_state);
+ }
out_free:
if (new_crtc_state)
intel_crtc_destroy_state(&crtc->base, &new_crtc_state->uapi);
if (ret)
intel_plane_destroy_state(&plane->base, &new_plane_state->uapi);
- else
+ else if (old_plane_state)
intel_plane_destroy_state(&plane->base, &old_plane_state->uapi);
return ret;
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 3effafcbb411a..9b43810f9a934 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -64,6 +64,7 @@
#include "intel_crt.h"
#include "intel_crtc.h"
#include "intel_crtc_state_dump.h"
+#include "intel_cursor.h"
#include "intel_ddi.h"
#include "intel_de.h"
#include "intel_display_driver.h"
@@ -6883,6 +6884,8 @@ static void intel_commit_modeset_disables(struct intel_atomic_state *state)
intel_pre_plane_update(state, crtc);
intel_crtc_disable_planes(state, crtc);
+
+ drm_vblank_work_flush_all(&crtc->base);
}
/* Only disable port sync and MST slaves */
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 926bf9c1a3ede..6d27cfb4f08e7 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -709,6 +709,9 @@ struct intel_plane_state {
struct intel_fb_view view;
+ /* for legacy cursor fb unpin */
+ struct drm_vblank_work unpin_work;
+
/* Plane pxp decryption state */
bool decrypt;
--
2.39.2
