[v3,10/13] drm/i915/dmc: Add interface to control start of PKG C-state exit

Commit Message

Hogander, Jouni April 14, 2025, 10:05 a.m. UTC

Add interface to control if package C exit starts at the start of the
undelayed vblank. This is needed to implement workaround for underrun on
idle PSR HW issue (Wa_16025596647).

Signed-off-by: Jouni Högander <[e-mail]>
---
 drivers/gpu/drm/i915/display/intel_dmc.c | 31 ++++++++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_dmc.h |  2 ++
 2 files changed, 33 insertions(+)

Patch

diff --git a/drivers/gpu/drm/i915/display/intel_dmc.c b/drivers/gpu/drm/i915/display/intel_dmc.c
index c65544e48c42..bd50c98c0ee4 100644
--- a/drivers/gpu/drm/i915/display/intel_dmc.c
+++ b/drivers/gpu/drm/i915/display/intel_dmc.c
@@ -534,6 +534,37 @@  void intel_dmc_block_pkgc(struct intel_display *display, enum pipe pipe,
 		     PIPEDMC_BLOCK_PKGC_SW_BLOCK_PKGC_ALWAYS : 0);
 }
 
+/**
+ * intel_dmc_start_pkgc_exit_at_start_of_undelayed_vblank() - start of PKG
+ * C-state exit
+ * @display: display instance
+ * @pipe: pipe which register use to block
+ * @enable: enable/disable
+ *
+ * This interface is target for Wa_16025596647 usage. I.e. start the package C
+ * exit at the start of the undelayed vblank
+ */
+void intel_dmc_start_pkgc_exit_at_start_of_undelayed_vblank(struct intel_display *display,
+							    enum pipe pipe, bool enable)
+{
+	u32 val;
+
+	if (enable)
+		val = DMC_EVT_CTL_ENABLE | DMC_EVT_CTL_RECURRING |
+			REG_FIELD_PREP(DMC_EVT_CTL_TYPE_MASK,
+				       DMC_EVT_CTL_TYPE_EDGE_0_1) |
+			REG_FIELD_PREP(DMC_EVT_CTL_EVENT_ID_MASK,
+				       DMC_EVT_CTL_EVENT_ID_VBLANK_A);
+	else
+		val = REG_FIELD_PREP(DMC_EVT_CTL_EVENT_ID_MASK,
+				     DMC_EVT_CTL_EVENT_ID_FALSE) |
+			REG_FIELD_PREP(DMC_EVT_CTL_TYPE_MASK,
+				       DMC_EVT_CTL_TYPE_EDGE_0_1);
+
+	intel_de_write(display, MTL_PIPEDMC_EVT_CTL_4(pipe),
+		       val);
+}
+
 static bool is_dmc_evt_ctl_reg(struct intel_display *display,
 			       enum intel_dmc_id dmc_id, i915_reg_t reg)
 {
diff --git a/drivers/gpu/drm/i915/display/intel_dmc.h b/drivers/gpu/drm/i915/display/intel_dmc.h
index 236312fb791c..bd1c459b0075 100644
--- a/drivers/gpu/drm/i915/display/intel_dmc.h
+++ b/drivers/gpu/drm/i915/display/intel_dmc.h
@@ -20,6 +20,8 @@  void intel_dmc_enable_pipe(struct intel_display *display, enum pipe pipe);
 void intel_dmc_disable_pipe(struct intel_display *display, enum pipe pipe);
 void intel_dmc_block_pkgc(struct intel_display *display, enum pipe pipe,
 			  bool block);
+void intel_dmc_start_pkgc_exit_at_start_of_undelayed_vblank(struct intel_display *display,
+							    enum pipe pipe, bool enable);
 void intel_dmc_fini(struct intel_display *display);
 void intel_dmc_suspend(struct intel_display *display);
 void intel_dmc_resume(struct intel_display *display);