On 6/16/2026 11:32 PM, Ville Syrjälä wrote:
On Mon, Jun 08, 2026 at 06:07:10PM +0530, Ankit Nautiyal wrote:
When the VRR timing generator is always used, the hardware behaves
as VRR-active regardless of crtc_state->vrr.enable.
The DSB paths that depend on the VRR safe window therefore need to follow
the VRR code paths in that case too:
- dsb_chicken(): program the SAFE_WINDOW chicken bits,
- intel_dsb_vblank_evade(): use vmin/vmax vblank starts for the
wait window,
- intel_dsb_wait_for_delayed_vblank(): wait inside the vmin safe window
before the scanline-based delayed vblank wait.
Introduce helper pre_commit_use_safe_window() and use it in the three sites
v2: Instead of modifying pre_commit_is_vrr_active() use a new helper and
use it only in the required places. (Ville).
Signed-off-by: Ankit Nautiyal <[email protected]>
---
drivers/gpu/drm/i915/display/intel_dsb.c | 20 ++++++++++++++++----
1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c
b/drivers/gpu/drm/i915/display/intel_dsb.c
index 07dd6318d9cc..d1441a86d1cc 100644
--- a/drivers/gpu/drm/i915/display/intel_dsb.c
+++ b/drivers/gpu/drm/i915/display/intel_dsb.c
@@ -210,6 +210,18 @@ static int dsb_scanline_to_hw(struct intel_atomic_state
*state,
return (scanline + vtotal - intel_crtc_scanline_offset(crtc_state)) %
vtotal;
}
+static
+bool pre_commit_use_safe_window(struct intel_atomic_state *state,
+ struct intel_crtc *crtc)
+{
+ struct intel_display *display = to_intel_display(crtc->base.dev);
+
+ if (intel_vrr_always_use_vrr_tg(display))
+ return true;
+
+ return pre_commit_is_vrr_active(state, crtc);
+}
+
/*
* Bspec suggests that we should always set DSB_SKIP_WAITS_EN. We have
approach
* different from what is explained in Bspec on how flip is considered being
@@ -229,7 +241,7 @@ static u32 dsb_chicken(struct intel_atomic_state *state,
u32 chicken = intel_psr_use_trans_push(new_crtc_state) ?
DSB_SKIP_WAITS_EN : 0;
- if (pre_commit_is_vrr_active(state, crtc))
+ if (pre_commit_use_safe_window(state, crtc))
chicken |= DSB_CTRL_WAIT_SAFE_WINDOW |
DSB_CTRL_NO_WAIT_VBLANK |
DSB_INST_WAIT_SAFE_WINDOW |
@@ -759,7 +771,7 @@ void intel_dsb_vblank_evade(struct intel_atomic_state
*state,
if (crtc_state->has_psr)
intel_dsb_emit_wait_dsl(dsb, DSB_OPCODE_WAIT_DSL_OUT, 0, 0);
- if (pre_commit_is_vrr_active(state, crtc) && crtc_state->vrr.dc_balance.enable) {
+ if (pre_commit_use_safe_window(state, crtc) &&
crtc_state->vrr.dc_balance.enable) {
This one I think should keep using pre_commit_is_vrr_active().
Yes you are right DC balance is always with VRR so
pre_commit_is_vrr_active() makes sense.
int vblank_delay = crtc_state->set_context_latency;
int vmin_vblank_start, vmax_vblank_start;
@@ -788,7 +800,7 @@ void intel_dsb_vblank_evade(struct intel_atomic_state *state,
end = vmax_vblank_start;
start = end - vblank_delay - latency;
intel_dsb_wait_scanline_out(state, dsb, start, end);
- } else if (pre_commit_is_vrr_active(state, crtc)) {
+ } else if (pre_commit_use_safe_window(state, crtc)) {
int vblank_delay = crtc_state->set_context_latency;
end = intel_vrr_vmin_vblank_start(crtc_state);
This will now emit two WAIT_DSL commands, which may be a bit confusing.
Might be better to add a completely separate branch to the if ladder
for this situation. And for consistency it should perhaps use
intel_mode_vblank_start() rather than intel_vrr_*_vblank_start()
since we're dealing with fixed refresh rate timings here.
Oh ok. Right.
I will add one more branches as suggested.
This will now have 4 branches:
-DC Balance + VRR [Needs pre_commit_is_vrr_active()]
-VRR without DC Balance [Needs pre_commit_is_vrr_active()]
-Fixed RR (always use VRR TG, NA for other platforms) [ Needs
pre_commit_use_safe_window()]
-Fixed RR (for other platforms (not always using VRR TG) [else]
I will fix this and re-send this patch.
Thanks for the guidance here. Its clearer to me now.
Regards,
Ankit
@@ -891,7 +903,7 @@ void intel_dsb_wait_for_delayed_vblank(struct
intel_atomic_state *state,
&crtc_state->hw.adjusted_mode;
int wait_scanlines;
- if (pre_commit_is_vrr_active(state, crtc)) {
+ if (pre_commit_use_safe_window(state, crtc)) {
/*
* If the push happened before the vmin decision boundary
* we don't know how far we are from the undelayed vblank.
--
2.45.2
