For throttling to work correctly, we always need a baseline vblank
count last_flip_vblank that increments at start of front-porch.
This is the case for drm_crtc_vblank_count() in non-VRR mode, where
the vblank irq fires at start of front-porch and triggers DRM core
vblank handling, but it is no longer the case in VRR mode, where
core vblank handling is done later, after end of front-porch.
Therefore drm_crtc_vblank_count() is no longer useful for this.
We also can't use drm_crtc_accurate_vblank_count(), as that would
screw up vblank timestamps in VRR mode when called in front-porch.
To solve this, use the cooked hardware vblank counter returned by
amdgpu_get_vblank_counter_kms() instead, as that one is cooked to
always increment at start of front-porch, independent of when
vblank related irq's fire.
This patch allows vblank irq handling to happen anywhere within
vblank of even after it, without a negative impact on flip
throttling, so followup patches can shift the vblank core
handling trigger point wherever they need it.
Signed-off-by: Mario Kleiner <mario.kleiner.de@xxxxxxxxx>
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h | 2 +-
.../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 23 +++++++++++--------
2 files changed, 14 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
index 889e443eeee7..add238fe4b57 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
@@ -406,7 +406,7 @@ struct amdgpu_crtc {
struct amdgpu_flip_work *pflip_works;
enum amdgpu_flip_status pflip_status;
int deferred_flip_completion;
- u64 last_flip_vblank;
+ u32 last_flip_vblank;
/* pll sharing */
struct amdgpu_atom_ss ss;
bool ss_enabled;
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 6c413bc012af..7366528e5cc2 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -286,7 +286,7 @@ static void dm_pflip_high_irq(void *interrupt_params)
}
/* Update to correct count(s) if racing with vblank irq */
- amdgpu_crtc->last_flip_vblank = drm_crtc_accurate_vblank_count(&amdgpu_crtc->base);
+ drm_crtc_accurate_vblank_count(&amdgpu_crtc->base);
/* wake up userspace */
if (amdgpu_crtc->event) {
@@ -298,6 +298,14 @@ static void dm_pflip_high_irq(void *interrupt_params)
} else
WARN_ON(1);
+ /* Keep track of vblank of this flip for flip throttling. We use the
+ * cooked hw counter, as that one incremented at start of this vblank
+ * of pageflip completion, so last_flip_vblank is the forbidden count
+ * for queueing new pageflips if vsync + VRR is enabled.
+ */
+ amdgpu_crtc->last_flip_vblank = amdgpu_get_vblank_counter_kms(adev->ddev,
+ amdgpu_crtc->crtc_id);
+
amdgpu_crtc->pflip_status = AMDGPU_FLIP_NONE;
spin_unlock_irqrestore(&adev->ddev->event_lock, flags);
@@ -4789,9 +4797,8 @@ static void amdgpu_dm_commit_planes(struct drm_atomic_state *state,
unsigned long flags;
struct amdgpu_bo *abo;
uint64_t tiling_flags;
- uint32_t target, target_vblank;
- uint64_t last_flip_vblank;
- bool vrr_active = acrtc_state->freesync_config.state == VRR_STATE_ACTIVE_VARIABLE;
+ uint32_t target_vblank, last_flip_vblank;
+ bool vrr_active = amdgpu_dm_vrr_active(acrtc_state);
bool pflip_present = false;
struct {
@@ -4935,7 +4942,7 @@ static void amdgpu_dm_commit_planes(struct drm_atomic_state *state,
* clients using the GLX_OML_sync_control extension or
* DRI3/Present extension with defined target_msc.
*/
- last_flip_vblank = drm_crtc_vblank_count(pcrtc);
+ last_flip_vblank = amdgpu_get_vblank_counter_kms(dm->ddev, acrtc_attach->crtc_id);
}
else {
/* For variable refresh rate mode only:
@@ -4951,11 +4958,7 @@ static void amdgpu_dm_commit_planes(struct drm_atomic_state *state,
spin_unlock_irqrestore(&pcrtc->dev->event_lock, flags);
}
- target = (uint32_t)last_flip_vblank + wait_for_vblank;
-
- /* Prepare wait for target vblank early - before the fence-waits */
- target_vblank = target - (uint32_t)drm_crtc_vblank_count(pcrtc) +
- amdgpu_get_vblank_counter_kms(pcrtc->dev, acrtc_attach->crtc_id);
+ target_vblank = last_flip_vblank + wait_for_vblank;
/*
* Wait until we're out of the vertical blank period before the one
--
2.20.1
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