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authorVille Syrjälä <ville.syrjala@linux.intel.com>2025-10-14 22:18:03 +0300
committerVille Syrjälä <ville.syrjala@linux.intel.com>2025-10-16 18:20:32 +0300
commit4157c75604c7adc87e1a5ae94074621bfad5a3fe (patch)
tree7e3932bdc30df07c897576cd948abd317f7a064a
parent2b4c2a5e4d7b26b884f3861108becae0098e3233 (diff)
drm/i915/cdclk: Add intel_cdclk_min_cdclk_for_prefill()
Introduce a helper to compute the min required cdclk frequency for a given guardband size. This could be used to bump up the cdclk in case the vblank is so small that the normally computed minimum cdclk results in too slow a prefill. Reviewed-by: Uma Shankar <uma.shankar@intel.com> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20251014191808.12326-5-ville.syrjala@linux.intel.com
-rw-r--r--drivers/gpu/drm/i915/display/intel_cdclk.c12
-rw-r--r--drivers/gpu/drm/i915/display/intel_cdclk.h3
2 files changed, 15 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c
index 10abc2521fab..bd45b719d4f8 100644
--- a/drivers/gpu/drm/i915/display/intel_cdclk.c
+++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
@@ -4120,3 +4120,15 @@ unsigned int intel_cdclk_prefill_adjustment_worst(const struct intel_crtc_state
return _intel_cdclk_prefill_adj(crtc_state, clock, min_cdclk);
}
+
+int intel_cdclk_min_cdclk_for_prefill(const struct intel_crtc_state *crtc_state,
+ unsigned int prefill_lines_unadjusted,
+ unsigned int prefill_lines_available)
+{
+ struct intel_display *display = to_intel_display(crtc_state);
+ const struct drm_display_mode *pipe_mode = &crtc_state->hw.pipe_mode;
+ int ppc = intel_cdclk_ppc(display, crtc_state->double_wide);
+
+ return DIV_ROUND_UP_ULL(mul_u32_u32(pipe_mode->crtc_clock, prefill_lines_unadjusted),
+ ppc * prefill_lines_available);
+}
diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.h b/drivers/gpu/drm/i915/display/intel_cdclk.h
index 8774a320670b..1c1140b53b17 100644
--- a/drivers/gpu/drm/i915/display/intel_cdclk.h
+++ b/drivers/gpu/drm/i915/display/intel_cdclk.h
@@ -72,5 +72,8 @@ void intel_cdclk_read_hw(struct intel_display *display);
unsigned int intel_cdclk_prefill_adjustment(const struct intel_crtc_state *crtc_state);
unsigned int intel_cdclk_prefill_adjustment_worst(const struct intel_crtc_state *crtc_state);
+int intel_cdclk_min_cdclk_for_prefill(const struct intel_crtc_state *crtc_state,
+ unsigned int prefill_lines_unadjusted,
+ unsigned int prefill_lines_available);
#endif /* __INTEL_CDCLK_H__ */