On 10/1/2025 5:42 PM, Ville Syrjälä wrote:
On Wed, Oct 01, 2025 at 04:11:13PM +0530, Nautiyal, Ankit K wrote:
On 9/29/2025 2:30 PM, Ville Syrjälä wrote:
On Sun, Sep 28, 2025 at 12:35:40PM +0530, Ankit Nautiyal wrote:
As we move towards using a shorter, optimized guardband, we need to adjust
how the delayed vblank start is computed.
Use the helper intel_vrr_compute_guardband() to calculate the optimized
guardband. Since this is measured from the vblank end, we shift the
vblank-start accordingly.
Calculate the minimum delay required based on the guardband and apply it in
intel_crtc_vblank_delay() to update crtc_vblank_start.
Additionally, introduce a new allow_vblank_delay_fastset() helper that
combines the existing LRR-based logic with an additional check for the
optimized guardband usage.
v2:
- Check if optimized guardband is more than vblank length and add debug
print.
- Extend vblank delay fastset logic to cover optimized guardband.
Signed-off-by: Ankit Nautiyal <ankit.k.nauti...@intel.com>
---
drivers/gpu/drm/i915/display/intel_display.c | 79 +++++++++++++++++++-
1 file changed, 76 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display.c
b/drivers/gpu/drm/i915/display/intel_display.c
index 4135f9be53fd..97a3121a204f 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -2361,6 +2361,67 @@ static int intel_crtc_compute_pipe_mode(struct
intel_crtc_state *crtc_state)
return 0;
}
+static
+int intel_crtc_min_guardband_delay(struct intel_atomic_state *state,
+ struct intel_crtc *crtc)
+{
+ struct intel_display *display = to_intel_display(state);
+ struct intel_crtc_state *crtc_state =
+ intel_atomic_get_new_crtc_state(state, crtc);
+ const struct drm_display_mode *adjusted_mode =
+ &crtc_state->hw.adjusted_mode;
+ struct drm_connector_state *conn_state;
+ struct drm_connector *drm_connector;
+ int vblank_length;
+ int i;
+
+ if (!intel_vrr_use_optimized_guardband(crtc_state))
+ return 0;
+
+ vblank_length = crtc_state->vrr.vmin -
+ adjusted_mode->crtc_vdisplay;
+
+ for_each_new_connector_in_state(&state->base,
+ drm_connector,
+ conn_state, i) {
+ int guardband;
+ struct intel_connector *connector;
+
+ if (conn_state->crtc != &crtc->base)
+ continue;
+
+ connector = to_intel_connector(drm_connector);
+ guardband = intel_vrr_compute_guardband(crtc_state,
+ connector);
+ if (guardband > vblank_length) {
+ drm_dbg_kms(display->drm,
+ "[CRTC:%d:%s] Cannot optimize guardband (%d)
exceeds max (%d)\n",
+ crtc->base.base.id, crtc->base.name,
+ guardband,
+ vblank_length);
+ return 0;
+ }
+
+ return vblank_length - guardband;
+ }
+
+ return 0;
+}
+
+static void intel_crtc_vblank_delay(struct intel_atomic_state *state,
+ struct intel_crtc *crtc)
+{
+ struct intel_crtc_state *crtc_state =
+ intel_atomic_get_new_crtc_state(state, crtc);
+ struct drm_display_mode *adjusted_mode =
+ &crtc_state->hw.adjusted_mode;
+ int vblank_delay = 0;
+
+ vblank_delay = intel_crtc_min_guardband_delay(state, crtc);
+
+ adjusted_mode->crtc_vblank_start += vblank_delay;
+}
+
static int intel_crtc_set_context_latency(struct intel_crtc_state
*crtc_state)
{
struct intel_display *display = to_intel_display(crtc_state);
@@ -2413,6 +2474,7 @@ static int intel_crtc_compute_config(struct
intel_atomic_state *state,
ret = intel_crtc_compute_set_context_latency(state, crtc);
if (ret)
return ret;
+ intel_crtc_vblank_delay(state, crtc);
IMO we should get rid of all this vblank_delay terminology here.
This one I think should just be our current
intel_vrr_compute_config_late() (renamed to eg.
intel_vrr_compute_guardband()).
Hmm ok so will rename this and call from intel_modeset_pipe_config_late().
I meant you should move the intel_vrr_compute_config_late() call
from intel_modeset_pipe_config_late() to here, and rename it to
eg. intel_vrr_compute_guardband().
Oh ok sorry I got it other way round. Will do as suggested.
Regards,
Ankit
