[PATCH v7 05/26] drm/i915/display: Move vblank put until after critical section

Maarten Lankhorst
2026-03-10T11:57:39Z

drm_crtc_vblank_put may take some locks, this should probably
not be the first thing we do after entering the time sensitive
part.

A better place is after programming is completed. Add a flag
to put the vblank after completion.

In the case of drm_vblank_work_schedule, we may not even need
to disable the vblank interrupt any more if it takes its own
reference.

Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
---
drivers/gpu/drm/i915/display/intel_cursor.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_cursor.c b/drivers/gpu/drm/i915/display/intel_cursor.c
index 18d1014de3613..5248e478b64e8 100644
--- a/drivers/gpu/drm/i915/display/intel_cursor.c
+++ b/drivers/gpu/drm/i915/display/intel_cursor.c
@@ -817,6 +817,7 @@ intel_legacy_cursor_update(struct drm_plane *_plane,
to_intel_crtc_state(crtc->base.state);
struct intel_crtc_state *new_crtc_state;
struct intel_vblank_evade_ctx evade;
+ bool has_vblank = false;
int ret;

/*
@@ -914,6 +915,8 @@ intel_legacy_cursor_update(struct drm_plane *_plane,
intel_psr_lock(crtc_state);

if (!drm_WARN_ON(display->drm, drm_crtc_vblank_get(&crtc->base))) {
+ has_vblank = true;
+
/*
* TODO: maybe check if we're still in PSR
* and skip the vblank evasion entirely?
@@ -923,8 +926,6 @@ intel_legacy_cursor_update(struct drm_plane *_plane,
local_irq_disable();

intel_vblank_evade(&evade);
-
- drm_crtc_vblank_put(&crtc->base);
} else {
local_irq_disable();
}
@@ -940,6 +941,9 @@ intel_legacy_cursor_update(struct drm_plane *_plane,

intel_psr_unlock(crtc_state);

+ if (has_vblank)
+ drm_crtc_vblank_put(&crtc->base);
+
if (old_plane_state->ggtt_vma != new_plane_state->ggtt_vma) {
drm_vblank_work_init(&old_plane_state->unpin_work, &crtc->base,
intel_cursor_unpin_work);
--
2.51.0