From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Looks like TRANS_CHICKEN bit 31 means something totally different
depending on the platform:
TGL: generate VRR "safe window" for DSB
ADL/DG2: make TRANS_SET_CONTEXT_LATENCY effective with VRR
So far we've only set this on ADL/DG2, but when using DSB+VRR
we also need to set it on TGL.
And a quick test on MTL says it doesn't need this bit for either
of those purposes, even though it's still documented as valid
in bspec.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 34d8311f4a1c ("drm/i915/dsb: Re-instate DSB for LUT updates")
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/9927
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_vrr.c | 7 ++++---
drivers/gpu/drm/i915/i915_reg.h | 2 +-
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index 5d905f932cb4..eb5bd0743902 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -187,10 +187,11 @@ void intel_vrr_set_transcoder_timings(const struct intel_crtc_state *crtc_state)
enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
/*
- * TRANS_SET_CONTEXT_LATENCY with VRR enabled
- * requires this chicken bit on ADL/DG2.
+ * This bit seems to have two meanings depending on the platform:
+ * TGL: generate VRR "safe window" for DSB vblank waits
+ * ADL/DG2: make TRANS_SET_CONTEXT_LATENCY effective with VRR
*/
- if (DISPLAY_VER(dev_priv) == 13)
+ if (IS_DISPLAY_VER(dev_priv, 12, 13))
intel_de_rmw(dev_priv, CHICKEN_TRANS(cpu_transcoder),
0, PIPE_VBLANK_WITH_DELAY);
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index e00557e1a57f..3b2e49ce29ba 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -4599,7 +4599,7 @@
#define MTL_CHICKEN_TRANS(trans) _MMIO_TRANS((trans), \
_MTL_CHICKEN_TRANS_A, \
_MTL_CHICKEN_TRANS_B)
-#define PIPE_VBLANK_WITH_DELAY REG_BIT(31) /* ADL/DG2 */
+#define PIPE_VBLANK_WITH_DELAY REG_BIT(31) /* tgl+ */
#define SKL_UNMASK_VBL_TO_PIPE_IN_SRD REG_BIT(30) /* skl+ */
#define HSW_FRAME_START_DELAY_MASK REG_GENMASK(28, 27)
#define HSW_FRAME_START_DELAY(x) REG_FIELD_PREP(HSW_FRAME_START_DELAY_MASK, x)
--
2.43.0
