From ff2be1671113ae1d2f81a5422969f65155b4f2fd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Wed, 17 Nov 2021 20:31:02 +0200
Subject: drm/i915: Do vblank evasion correctly if vrr push has already been
sent
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Git-commit: 0088d39b6ad9f7d814c10e7188aba0ddbc737883
Patch-mainline: v5.17-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
Let's adjust the vblank evasion to account for the case where
a push has already been sent. In that case the vblank exit will start
at vmin vblank start (as opposed to vmax vblank start when no push
has been sent).
This should minimize the effects of the tiny race between sampling
the frame counter vs. intel_vrr_send_push() during the previous frame.
This will also be required if we want to do mailbox style updates with
vrr since then we'd definitely do multiple commits per frame. Currently
mailbox updates are only used by the legacy cursor, but we don't do
vrr push for those.
Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211117183103.27418-2-ville.syrjala@linux.intel.com
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/display/intel_crtc.c | 10 +++++++---
drivers/gpu/drm/i915/display/intel_vrr.c | 12 ++++++++++++
drivers/gpu/drm/i915/display/intel_vrr.h | 1 +
3 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_crtc.c b/drivers/gpu/drm/i915/display/intel_crtc.c
index cf403be7736c..eb5444f90e77 100644
--- a/drivers/gpu/drm/i915/display/intel_crtc.c
+++ b/drivers/gpu/drm/i915/display/intel_crtc.c
@@ -470,10 +470,14 @@ void intel_pipe_update_start(struct intel_crtc_state *new_crtc_state)
if (intel_crtc_needs_vblank_work(new_crtc_state))
intel_crtc_vblank_work_init(new_crtc_state);
- if (new_crtc_state->vrr.enable)
- vblank_start = intel_vrr_vmax_vblank_start(new_crtc_state);
- else
+ if (new_crtc_state->vrr.enable) {
+ if (intel_vrr_is_push_sent(new_crtc_state))
+ vblank_start = intel_vrr_vmin_vblank_start(new_crtc_state);
+ else
+ vblank_start = intel_vrr_vmax_vblank_start(new_crtc_state);
+ } else {
vblank_start = intel_mode_vblank_start(adjusted_mode);
+ }
/* FIXME needs to be calibrated sensibly */
min = vblank_start - intel_usecs_to_scanlines(adjusted_mode,
diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c
index c335b1dbafcf..db1c3902fc2d 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.c
+++ b/drivers/gpu/drm/i915/display/intel_vrr.c
@@ -193,6 +193,18 @@ void intel_vrr_send_push(const struct intel_crtc_state *crtc_state)
TRANS_PUSH_EN | TRANS_PUSH_SEND);
}
+bool intel_vrr_is_push_sent(const struct intel_crtc_state *crtc_state)
+{
+ struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+ struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+ enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
+
+ if (!crtc_state->vrr.enable)
+ return false;
+
+ return intel_de_read(dev_priv, TRANS_PUSH(cpu_transcoder)) & TRANS_PUSH_SEND;
+}
+
void intel_vrr_disable(const struct intel_crtc_state *old_crtc_state)
{
struct intel_crtc *crtc = to_intel_crtc(old_crtc_state->uapi.crtc);
diff --git a/drivers/gpu/drm/i915/display/intel_vrr.h b/drivers/gpu/drm/i915/display/intel_vrr.h
index 96f9c9c27ab9..1c2da572693d 100644
--- a/drivers/gpu/drm/i915/display/intel_vrr.h
+++ b/drivers/gpu/drm/i915/display/intel_vrr.h
@@ -23,6 +23,7 @@ void intel_vrr_compute_config(struct intel_crtc_state *crtc_state,
void intel_vrr_enable(struct intel_encoder *encoder,
const struct intel_crtc_state *crtc_state);
void intel_vrr_send_push(const struct intel_crtc_state *crtc_state);
+bool intel_vrr_is_push_sent(const struct intel_crtc_state *crtc_state);
void intel_vrr_disable(const struct intel_crtc_state *old_crtc_state);
void intel_vrr_get_config(struct intel_crtc *crtc,
struct intel_crtc_state *crtc_state);
--
2.38.1