[PATCH 2/2] drm/i915/display: Avoid use of VTOTAL.Vtotal bits

[Ankit Nautiyal]

For platforms that always use VRR Timing Generator, the VTOTAL.Vtotal
bits are not required. Since the support for these bits is going to
be deprecated in upcoming platforms, avoid writing these bits for the
platforms that do not use legacy Timing Generator.

Since for these platforms vrr.vmin is always filled with crtc_vtotal,
use TRAN_VRR_VMIN to get the vtotal for adjusted_mode.

v2: Avoid having a helper for manipulating VTOTAL register, and instead
just make the change where required. (Ville)
v3: Set crtc_vtotal instead of working with the bits directly (Ville).
Use intel_vrr_vmin_vtotal() to set the vtotal during readout. (Ville)
v4: Keep the reading part unchanged, and let it get overwritten for
cases where we use vrr.vmin. (Ville)

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c | 18 ++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_vrr.c     | 10 ++++++++++
 2 files changed, 28 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index b82b3d63be73..b447fca1c616 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -2698,6 +2698,15 @@ static void intel_set_transcoder_timings(const struct intel_crtc_state *crtc_sta
 		       HSYNC_START(adjusted_mode->crtc_hsync_start - 1) |
 		       HSYNC_END(adjusted_mode->crtc_hsync_end - 1));
 
+	/*
+	 * For platforms that always use VRR Timing Generator, the VTOTAL.Vtotal
+	 * bits are not required. Since the support for these bits is going to
+	 * be deprecated in upcoming platforms, avoid writing these bits for the
+	 * platforms that do not use legacy Timing Generator.
+	 */
+	if (intel_vrr_always_use_vrr_tg(display))
+		crtc_vtotal = 1;
+
 	intel_de_write(display, TRANS_VTOTAL(display, cpu_transcoder),
 		       VACTIVE(crtc_vdisplay - 1) |
 		       VTOTAL(crtc_vtotal - 1));
@@ -2758,6 +2767,15 @@ static void intel_set_transcoder_timings_lrr(const struct intel_crtc_state *crtc
 	intel_de_write(display, TRANS_VBLANK(display, cpu_transcoder),
 		       VBLANK_START(crtc_vblank_start - 1) |
 		       VBLANK_END(crtc_vblank_end - 1));
+	/*
+	 * For platforms that always use VRR Timing Generator, the VTOTAL.Vtotal
+	 * bits are not required. Since the support for these bits is going to
+	 * be deprecated in upcoming platforms, avoid writing these bits for the
+	 * platforms that do not use legacy Timing Generator.
+	 */
+	if (intel_vrr_always_use_vrr_tg(display))
+		crtc_vtotal = 1;
+
 	/*
 	 * The double buffer latch point for TRANS_VTOTAL
 	 * is the transcoder's undelayed vblank.
diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index 414f93851059..7359d66fc091 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -708,6 +708,16 @@ void intel_vrr_get_config(struct intel_crtc_state *crtc_state)
 		crtc_state->vrr.vmin = intel_de_read(display,
 						     TRANS_VRR_VMIN(display, cpu_transcoder)) + 1;
 
+		/*
+		 * For platforms that always use VRR Timing Generator, the VTOTAL.Vtotal
+		 * bits are not filled. Since for these platforms TRAN_VMIN is always
+		 * filled with crtc_vtotal, use TRAN_VRR_VMIN to get the vtotal for
+		 * adjusted_mode.
+		 */
+		if (intel_vrr_always_use_vrr_tg(display))
+			crtc_state->hw.adjusted_mode.crtc_vtotal =
+				intel_vrr_vmin_vtotal(crtc_state);
+
 		if (HAS_AS_SDP(display)) {
 			trans_vrr_vsync =
 				intel_de_read(display,
-- 
2.45.2