[PATCH 2/4] drm/i915/display/psr: Lock and unlock PSR around pipe updates
José Roberto de Souza
jose.souza at intel.com
Fri Apr 1 13:38:48 UTC 2022
Frontbuffer rendering and page flips can race with each other
and this can potentialy cause issues with PSR2 selective fetch.
And because pipe/crtc updates are time sentive we can't grab the
PSR lock after intel_pipe_update_start() and before
intel_pipe_update_end().
So here adding the lock and unlock functions and calls, the
proper PSR2 selective fetch handling will come in a separated patch.
Cc: Jouni Högander <jouni.hogander at intel.com>
Cc: Mika Kahola <mika.kahola at intel.com>
Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
---
drivers/gpu/drm/i915/display/intel_crtc.c | 17 +++---
drivers/gpu/drm/i915/display/intel_psr.c | 69 ++++++++++++++++++++---
drivers/gpu/drm/i915/display/intel_psr.h | 5 +-
3 files changed, 75 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_crtc.c b/drivers/gpu/drm/i915/display/intel_crtc.c
index f655c16228776..808c6500ac1b1 100644
--- a/drivers/gpu/drm/i915/display/intel_crtc.c
+++ b/drivers/gpu/drm/i915/display/intel_crtc.c
@@ -493,6 +493,14 @@ 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);
+ intel_psr_lock(new_crtc_state);
+ /*
+ * Wait for psr to idle out after enabling the VBL interrupts
+ * VBL interrupts will start the PSR exit and prevent a PSR
+ * re-entry as well.
+ */
+ intel_psr_wait_for_idle_locked(new_crtc_state);
+
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);
@@ -513,13 +521,6 @@ void intel_pipe_update_start(struct intel_crtc_state *new_crtc_state)
if (drm_WARN_ON(&dev_priv->drm, drm_crtc_vblank_get(&crtc->base)))
goto irq_disable;
- /*
- * Wait for psr to idle out after enabling the VBL interrupts
- * VBL interrupts will start the PSR exit and prevent a PSR
- * re-entry as well.
- */
- intel_psr_wait_for_idle(new_crtc_state);
-
local_irq_disable();
crtc->debug.min_vbl = min;
@@ -683,6 +684,8 @@ void intel_pipe_update_end(struct intel_crtc_state *new_crtc_state)
local_irq_enable();
+ intel_psr_unlock(new_crtc_state);
+
if (intel_vgpu_active(dev_priv))
return;
diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index 2da2468f555ec..58597480054eb 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -1548,10 +1548,19 @@ void intel_psr2_program_plane_sel_fetch(struct intel_plane *plane,
void intel_psr2_program_trans_man_trk_ctl(const struct intel_crtc_state *crtc_state)
{
struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);
+ struct intel_encoder *encoder;
if (!crtc_state->enable_psr2_sel_fetch)
return;
+ for_each_intel_encoder_mask_with_psr(&dev_priv->drm, encoder,
+ crtc_state->uapi.encoder_mask) {
+ struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
+
+ lockdep_assert_held(&intel_dp->psr.lock);
+ break;
+ }
+
intel_de_write(dev_priv, PSR2_MAN_TRK_CTL(crtc_state->cpu_transcoder),
crtc_state->psr2_man_track_ctl);
}
@@ -1919,13 +1928,13 @@ static int _psr1_ready_for_pipe_update_locked(struct intel_dp *intel_dp)
}
/**
- * intel_psr_wait_for_idle - wait for PSR be ready for a pipe update
+ * intel_psr_wait_for_idle_locked - wait for PSR be ready for a pipe update
* @new_crtc_state: new CRTC state
*
* This function is expected to be called from pipe_update_start() where it is
* not expected to race with PSR enable or disable.
*/
-void intel_psr_wait_for_idle(const struct intel_crtc_state *new_crtc_state)
+void intel_psr_wait_for_idle_locked(const struct intel_crtc_state *new_crtc_state)
{
struct drm_i915_private *dev_priv = to_i915(new_crtc_state->uapi.crtc->dev);
struct intel_encoder *encoder;
@@ -1938,12 +1947,10 @@ void intel_psr_wait_for_idle(const struct intel_crtc_state *new_crtc_state)
struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
int ret;
- mutex_lock(&intel_dp->psr.lock);
+ lockdep_assert_held(&intel_dp->psr.lock);
- if (!intel_dp->psr.enabled) {
- mutex_unlock(&intel_dp->psr.lock);
+ if (!intel_dp->psr.enabled)
continue;
- }
if (intel_dp->psr.psr2_enabled)
ret = _psr2_ready_for_pipe_update_locked(intel_dp);
@@ -1952,8 +1959,6 @@ void intel_psr_wait_for_idle(const struct intel_crtc_state *new_crtc_state)
if (ret)
drm_err(&dev_priv->drm, "PSR wait timed out, atomic update may fail\n");
-
- mutex_unlock(&intel_dp->psr.lock);
}
}
@@ -2444,3 +2449,51 @@ bool intel_psr_enabled(struct intel_dp *intel_dp)
return ret;
}
+
+/**
+ * intel_psr_lock - grab psr.lock mutex
+ * @crtc_state: the crtc state
+ *
+ * This is initially meant to be used by around CRTC update, when
+ * vblank sensitive registers are updated and we need grab the lock
+ * before it to avoid vblank evasion.
+ */
+void intel_psr_lock(const struct intel_crtc_state *crtc_state)
+{
+ struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
+ struct intel_encoder *encoder;
+
+ if (!crtc_state->has_psr)
+ return;
+
+ for_each_intel_encoder_mask_with_psr(&i915->drm, encoder,
+ crtc_state->uapi.encoder_mask) {
+ struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
+
+ mutex_lock(&intel_dp->psr.lock);
+ break;
+ }
+}
+
+/**
+ * intel_psr_lock - grab psr.lock mutex
+ * @crtc_state: the crtc state
+ *
+ * Release the PSR lock that was held during pipe update.
+ */
+void intel_psr_unlock(const struct intel_crtc_state *crtc_state)
+{
+ struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
+ struct intel_encoder *encoder;
+
+ if (!crtc_state->has_psr)
+ return;
+
+ for_each_intel_encoder_mask_with_psr(&i915->drm, encoder,
+ crtc_state->uapi.encoder_mask) {
+ struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
+
+ mutex_unlock(&intel_dp->psr.lock);
+ break;
+ }
+}
diff --git a/drivers/gpu/drm/i915/display/intel_psr.h b/drivers/gpu/drm/i915/display/intel_psr.h
index f6526d9ccfdc6..2ac3a46cccc50 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.h
+++ b/drivers/gpu/drm/i915/display/intel_psr.h
@@ -41,7 +41,7 @@ void intel_psr_get_config(struct intel_encoder *encoder,
struct intel_crtc_state *pipe_config);
void intel_psr_irq_handler(struct intel_dp *intel_dp, u32 psr_iir);
void intel_psr_short_pulse(struct intel_dp *intel_dp);
-void intel_psr_wait_for_idle(const struct intel_crtc_state *new_crtc_state);
+void intel_psr_wait_for_idle_locked(const struct intel_crtc_state *new_crtc_state);
bool intel_psr_enabled(struct intel_dp *intel_dp);
int intel_psr2_sel_fetch_update(struct intel_atomic_state *state,
struct intel_crtc *crtc);
@@ -55,4 +55,7 @@ void intel_psr2_disable_plane_sel_fetch(struct intel_plane *plane,
void intel_psr_pause(struct intel_dp *intel_dp);
void intel_psr_resume(struct intel_dp *intel_dp);
+void intel_psr_lock(const struct intel_crtc_state *crtc_state);
+void intel_psr_unlock(const struct intel_crtc_state *crtc_state);
+
#endif /* __INTEL_PSR_H__ */
--
2.35.1
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