drm/i915/dsb: Garbage collect the MMIO DEwake stuff

Since the introduction of DSB chaining we no longer need the
DEwake tricks in intel_dsb_commit().

I also need to relocate the DSB_PMCTRL* writes out of
intel_dsb_finish() (due to the flip queue DMC vs. DSB register
corruption issues), and it'll be a bit more straightforward if
I don't have to worry about the non-chained DSB path anymore.

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/20250612145018.8735-5-ville.syrjala@linux.intel.com

3 files changed, 11 insertions, 41 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index b0c7c46ffbe2..6ec786198f43 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -6748,13 +6748,13 @@ static void intel_update_crtc(struct intel_atomic_state *state,
 	if (new_crtc_state->use_dsb) {
 		intel_crtc_prepare_vblank_event(new_crtc_state, &crtc->dsb_event);
 
-		intel_dsb_commit(new_crtc_state->dsb_commit, false);
+		intel_dsb_commit(new_crtc_state->dsb_commit);
 	} else {
 		/* Perform vblank evasion around commit operation */
 		intel_pipe_update_start(state, crtc);
 
 		if (new_crtc_state->dsb_commit)
-			intel_dsb_commit(new_crtc_state->dsb_commit, false);
+			intel_dsb_commit(new_crtc_state->dsb_commit);
 
 		commit_pipe_pre_planes(state, crtc);
 
diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c
index 06a615d36a86..2f7bd8da1bf1 100644
--- a/drivers/gpu/drm/i915/display/intel_dsb.c
+++ b/drivers/gpu/drm/i915/display/intel_dsb.c
@@ -825,8 +825,13 @@ void intel_dsb_wait_vblank_delay(struct intel_atomic_state *state,
 	intel_dsb_wait_usec(dsb, usecs);
 }
 
-static void _intel_dsb_commit(struct intel_dsb *dsb, u32 ctrl,
-			      int hw_dewake_scanline)
+/**
+ * intel_dsb_commit() - Trigger workload execution of DSB.
+ * @dsb: DSB context
+ *
+ * This function is used to do actual write to hardware using DSB.
+ */
+void intel_dsb_commit(struct intel_dsb *dsb)
 {
 	struct intel_crtc *crtc = dsb->crtc;
 	struct intel_display *display = to_intel_display(crtc->base.dev);
@@ -842,7 +847,7 @@ static void _intel_dsb_commit(struct intel_dsb *dsb, u32 ctrl,
 	}
 
 	intel_de_write_fw(display, DSB_CTRL(pipe, dsb->id),
-			  ctrl | DSB_ENABLE);
+			  DSB_ENABLE);
 
 	intel_de_write_fw(display, DSB_CHICKEN(pipe, dsb->id),
 			  dsb->chicken);
@@ -854,44 +859,10 @@ static void _intel_dsb_commit(struct intel_dsb *dsb, u32 ctrl,
 	intel_de_write_fw(display, DSB_HEAD(pipe, dsb->id),
 			  intel_dsb_head(dsb));
 
-	if (hw_dewake_scanline >= 0) {
-		int diff, position;
-
-		intel_de_write_fw(display, DSB_PMCTRL(pipe, dsb->id),
-				  DSB_ENABLE_DEWAKE |
-				  DSB_SCANLINE_FOR_DEWAKE(hw_dewake_scanline));
-
-		/*
-		 * Force DEwake immediately if we're already past
-		 * or close to racing past the target scanline.
-		 */
-		position = intel_de_read_fw(display, PIPEDSL(display, pipe)) & PIPEDSL_LINE_MASK;
-
-		diff = hw_dewake_scanline - position;
-		intel_de_write_fw(display, DSB_PMCTRL_2(pipe, dsb->id),
-				  (diff >= 0 && diff < 5 ? DSB_FORCE_DEWAKE : 0) |
-				  DSB_BLOCK_DEWAKE_EXTENSION);
-	}
-
 	intel_de_write_fw(display, DSB_TAIL(pipe, dsb->id),
 			  intel_dsb_tail(dsb));
 }
 
-/**
- * intel_dsb_commit() - Trigger workload execution of DSB.
- * @dsb: DSB context
- * @wait_for_vblank: wait for vblank before executing
- *
- * This function is used to do actual write to hardware using DSB.
- */
-void intel_dsb_commit(struct intel_dsb *dsb,
-		      bool wait_for_vblank)
-{
-	_intel_dsb_commit(dsb,
-			  wait_for_vblank ? DSB_WAIT_FOR_VBLANK : 0,
-			  wait_for_vblank ? dsb->hw_dewake_scanline : -1);
-}
-
 void intel_dsb_wait(struct intel_dsb *dsb)
 {
 	struct intel_crtc *crtc = dsb->crtc;
diff --git a/drivers/gpu/drm/i915/display/intel_dsb.h b/drivers/gpu/drm/i915/display/intel_dsb.h
index 6bcfb03f3415..c8f4499916eb 100644
--- a/drivers/gpu/drm/i915/display/intel_dsb.h
+++ b/drivers/gpu/drm/i915/display/intel_dsb.h
@@ -68,8 +68,7 @@ void intel_dsb_chain(struct intel_atomic_state *state,
 		     struct intel_dsb *chained_dsb,
 		     bool wait_for_vblank);
 
-void intel_dsb_commit(struct intel_dsb *dsb,
-		      bool wait_for_vblank);
+void intel_dsb_commit(struct intel_dsb *dsb);
 void intel_dsb_wait(struct intel_dsb *dsb);
 
 void intel_dsb_irq_handler(struct intel_display *display,