[PATCH 01/10] drm/msm/dpu: unwind async commit handling

From: Rob Clark
Date: Thu Aug 29 2019 - 12:51:30 EST


From: Rob Clark <robdclark@xxxxxxxxxxxx>

It attempted to avoid fps drops in the presence of cursor updates. But
it is racing, and can result in hw updates after flush before vblank,
which leads to underruns.

Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
Reviewed-by: Sean Paul <sean@xxxxxxxxxx>
---
drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 41 ++++++++++-----------
drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h | 3 +-
drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 39 +++++++-------------
drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h | 3 +-
drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 5 +--
drivers/gpu/drm/msm/msm_atomic.c | 3 +-
6 files changed, 37 insertions(+), 57 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
index a52439e029c9..c3f7154017c4 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
@@ -610,7 +610,7 @@ static int _dpu_crtc_wait_for_frame_done(struct drm_crtc *crtc)
return rc;
}

-void dpu_crtc_commit_kickoff(struct drm_crtc *crtc, bool async)
+void dpu_crtc_commit_kickoff(struct drm_crtc *crtc)
{
struct drm_encoder *encoder;
struct dpu_crtc *dpu_crtc = to_dpu_crtc(crtc);
@@ -636,35 +636,32 @@ void dpu_crtc_commit_kickoff(struct drm_crtc *crtc, bool async)
crtc->state->encoder_mask)
dpu_encoder_prepare_for_kickoff(encoder);

- if (!async) {
- /* wait for previous frame_event_done completion */
- DPU_ATRACE_BEGIN("wait_for_frame_done_event");
- ret = _dpu_crtc_wait_for_frame_done(crtc);
- DPU_ATRACE_END("wait_for_frame_done_event");
- if (ret) {
- DPU_ERROR("crtc%d wait for frame done failed;frame_pending%d\n",
- crtc->base.id,
- atomic_read(&dpu_crtc->frame_pending));
- goto end;
- }
+ /* wait for previous frame_event_done completion */
+ DPU_ATRACE_BEGIN("wait_for_frame_done_event");
+ ret = _dpu_crtc_wait_for_frame_done(crtc);
+ DPU_ATRACE_END("wait_for_frame_done_event");
+ if (ret) {
+ DPU_ERROR("crtc%d wait for frame done failed;frame_pending%d\n",
+ crtc->base.id,
+ atomic_read(&dpu_crtc->frame_pending));
+ goto end;
+ }

- if (atomic_inc_return(&dpu_crtc->frame_pending) == 1) {
- /* acquire bandwidth and other resources */
- DPU_DEBUG("crtc%d first commit\n", crtc->base.id);
- } else
- DPU_DEBUG("crtc%d commit\n", crtc->base.id);
+ if (atomic_inc_return(&dpu_crtc->frame_pending) == 1) {
+ /* acquire bandwidth and other resources */
+ DPU_DEBUG("crtc%d first commit\n", crtc->base.id);
+ } else
+ DPU_DEBUG("crtc%d commit\n", crtc->base.id);

- dpu_crtc->play_count++;
- }
+ dpu_crtc->play_count++;

dpu_vbif_clear_errors(dpu_kms);

drm_for_each_encoder_mask(encoder, crtc->dev, crtc->state->encoder_mask)
- dpu_encoder_kickoff(encoder, async);
+ dpu_encoder_kickoff(encoder);

end:
- if (!async)
- reinit_completion(&dpu_crtc->frame_done_comp);
+ reinit_completion(&dpu_crtc->frame_done_comp);
DPU_ATRACE_END("crtc_commit");
}

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
index 5181f079a6a1..10f78459f6c2 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
@@ -238,9 +238,8 @@ void dpu_crtc_vblank_callback(struct drm_crtc *crtc);
/**
* dpu_crtc_commit_kickoff - trigger kickoff of the commit for this crtc
* @crtc: Pointer to drm crtc object
- * @async: true if the commit is asynchronous, false otherwise
*/
-void dpu_crtc_commit_kickoff(struct drm_crtc *crtc, bool async);
+void dpu_crtc_commit_kickoff(struct drm_crtc *crtc);

/**
* dpu_crtc_complete_commit - callback signalling completion of current commit
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
index 627c57594221..ac2d534bf59e 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
@@ -1421,8 +1421,7 @@ static void dpu_encoder_off_work(struct work_struct *work)
* extra_flush_bits: Additional bit mask to include in flush trigger
*/
static void _dpu_encoder_trigger_flush(struct drm_encoder *drm_enc,
- struct dpu_encoder_phys *phys, uint32_t extra_flush_bits,
- bool async)
+ struct dpu_encoder_phys *phys, uint32_t extra_flush_bits)
{
struct dpu_hw_ctl *ctl;
int pending_kickoff_cnt;
@@ -1439,10 +1438,7 @@ static void _dpu_encoder_trigger_flush(struct drm_encoder *drm_enc,
return;
}

- if (!async)
- pending_kickoff_cnt = dpu_encoder_phys_inc_pending(phys);
- else
- pending_kickoff_cnt = atomic_read(&phys->pending_kickoff_cnt);
+ pending_kickoff_cnt = dpu_encoder_phys_inc_pending(phys);

if (extra_flush_bits && ctl->ops.update_pending_flush)
ctl->ops.update_pending_flush(ctl, extra_flush_bits);
@@ -1553,8 +1549,7 @@ static void dpu_encoder_helper_hw_reset(struct dpu_encoder_phys *phys_enc)
* a time.
* dpu_enc: Pointer to virtual encoder structure
*/
-static void _dpu_encoder_kickoff_phys(struct dpu_encoder_virt *dpu_enc,
- bool async)
+static void _dpu_encoder_kickoff_phys(struct dpu_encoder_virt *dpu_enc)
{
struct dpu_hw_ctl *ctl;
uint32_t i, pending_flush;
@@ -1581,13 +1576,12 @@ static void _dpu_encoder_kickoff_phys(struct dpu_encoder_virt *dpu_enc,
* for async commits. So don't set this for async, since it'll
* roll over to the next commit.
*/
- if (!async && phys->split_role != ENC_ROLE_SLAVE)
+ if (phys->split_role != ENC_ROLE_SLAVE)
set_bit(i, dpu_enc->frame_busy_mask);

if (!phys->ops.needs_single_flush ||
!phys->ops.needs_single_flush(phys))
- _dpu_encoder_trigger_flush(&dpu_enc->base, phys, 0x0,
- async);
+ _dpu_encoder_trigger_flush(&dpu_enc->base, phys, 0x0);
else if (ctl->ops.get_pending_flush)
pending_flush |= ctl->ops.get_pending_flush(ctl);
}
@@ -1597,7 +1591,7 @@ static void _dpu_encoder_kickoff_phys(struct dpu_encoder_virt *dpu_enc,
_dpu_encoder_trigger_flush(
&dpu_enc->base,
dpu_enc->cur_master,
- pending_flush, async);
+ pending_flush);
}

_dpu_encoder_trigger_start(dpu_enc->cur_master);
@@ -1815,11 +1809,12 @@ void dpu_encoder_prepare_for_kickoff(struct drm_encoder *drm_enc)
}
}

-void dpu_encoder_kickoff(struct drm_encoder *drm_enc, bool async)
+void dpu_encoder_kickoff(struct drm_encoder *drm_enc)
{
struct dpu_encoder_virt *dpu_enc;
struct dpu_encoder_phys *phys;
ktime_t wakeup_time;
+ unsigned long timeout_ms;
unsigned int i;

DPU_ATRACE_BEGIN("encoder_kickoff");
@@ -1827,23 +1822,15 @@ void dpu_encoder_kickoff(struct drm_encoder *drm_enc, bool async)

trace_dpu_enc_kickoff(DRMID(drm_enc));

- /*
- * Asynchronous frames don't handle FRAME_DONE events. As such, they
- * shouldn't enable the frame_done watchdog since it will always time
- * out.
- */
- if (!async) {
- unsigned long timeout_ms;
- timeout_ms = DPU_ENCODER_FRAME_DONE_TIMEOUT_FRAMES * 1000 /
+ timeout_ms = DPU_ENCODER_FRAME_DONE_TIMEOUT_FRAMES * 1000 /
drm_mode_vrefresh(&drm_enc->crtc->state->adjusted_mode);

- atomic_set(&dpu_enc->frame_done_timeout_ms, timeout_ms);
- mod_timer(&dpu_enc->frame_done_timer,
- jiffies + msecs_to_jiffies(timeout_ms));
- }
+ atomic_set(&dpu_enc->frame_done_timeout_ms, timeout_ms);
+ mod_timer(&dpu_enc->frame_done_timer,
+ jiffies + msecs_to_jiffies(timeout_ms));

/* All phys encs are ready to go, trigger the kickoff */
- _dpu_encoder_kickoff_phys(dpu_enc, async);
+ _dpu_encoder_kickoff_phys(dpu_enc);

/* allow phys encs to handle any post-kickoff business */
for (i = 0; i < dpu_enc->num_phys_encs; i++) {
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
index 997d131c2440..8465b37adf3b 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
@@ -82,9 +82,8 @@ void dpu_encoder_trigger_kickoff_pending(struct drm_encoder *encoder);
* dpu_encoder_kickoff - trigger a double buffer flip of the ctl path
* (i.e. ctl flush and start) immediately.
* @encoder: encoder pointer
- * @async: true if this is an asynchronous commit
*/
-void dpu_encoder_kickoff(struct drm_encoder *encoder, bool async);
+void dpu_encoder_kickoff(struct drm_encoder *encoder);

/**
* dpu_encoder_wait_for_event - Waits for encoder events
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
index b8d264bd15df..31454cc5d8c5 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
@@ -298,7 +298,7 @@ void dpu_kms_encoder_enable(struct drm_encoder *encoder)
continue;

trace_dpu_kms_enc_enable(DRMID(crtc));
- dpu_crtc_commit_kickoff(crtc, false);
+ dpu_crtc_commit_kickoff(crtc);
}
}

@@ -315,8 +315,7 @@ static void dpu_kms_commit(struct msm_kms *kms, struct drm_atomic_state *state)

if (crtc->state->active) {
trace_dpu_kms_commit(DRMID(crtc));
- dpu_crtc_commit_kickoff(crtc,
- state->legacy_cursor_update);
+ dpu_crtc_commit_kickoff(crtc);
}
}
}
diff --git a/drivers/gpu/drm/msm/msm_atomic.c b/drivers/gpu/drm/msm/msm_atomic.c
index dd16babdd8c0..e5aae1645933 100644
--- a/drivers/gpu/drm/msm/msm_atomic.c
+++ b/drivers/gpu/drm/msm/msm_atomic.c
@@ -70,8 +70,7 @@ void msm_atomic_commit_tail(struct drm_atomic_state *state)
kms->funcs->commit(kms, state);
}

- if (!state->legacy_cursor_update)
- msm_atomic_wait_for_commit_done(dev, state);
+ msm_atomic_wait_for_commit_done(dev, state);

kms->funcs->complete_commit(kms, state);

--
2.21.0