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drm/msm/dpu: fix "frame done" timeouts

Browse source 
Previously, dpu_crtc_frame_event_work() would try to aquire all the
modeset locks in order to check whether it can release bandwidth.  (If
we only have cmd-mode display, bandwidth can be released at frame-done
time.)

The problem with this is that it is also responsible for signalling
frame_done_comp, which dpu_crtc_commit_kickoff() waits on if there is
already a frame pending.  This is called in the msm_atomic_commit_tail()
path.. which means that for non-nonblock commits, at least some of the
modeset locks are already held.

Re-work this scheme to use a reference count to track our need to have
clocks enabled.  It is incremented for each atomic commit, and
decremented in the corresponding frame-done.  Additionally, any crtc
used in video mode hold an extra reference while they are enabled.  The
net effect is that we can determine in frame-done whether it is safe to
drop bandwidth without needing to aquire any modeset locks.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Sean Paul <sean@chromium.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>
This commit is contained in:
Rob Clark 2019-08-20 16:12:28 -07:00
parent ed98359a9e
commit 241b507c16
4 changed files with 38 additions and 33 deletions
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16
drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c
View file

@ -214,7 +214,6 @@ static int _dpu_core_perf_crtc_update_bus(struct dpu_kms *kms,
*/
void dpu_core_perf_crtc_release_bw(struct drm_crtc *crtc)
{
struct drm_crtc *tmp_crtc;
struct dpu_crtc *dpu_crtc;
struct dpu_crtc_state *dpu_cstate;
struct dpu_kms *kms;
@ -233,22 +232,9 @@ void dpu_core_perf_crtc_release_bw(struct drm_crtc *crtc)
dpu_crtc = to_dpu_crtc(crtc);
dpu_cstate = to_dpu_crtc_state(crtc->state);
/* only do this for command mode rt client */
if (dpu_crtc_get_intf_mode(crtc) != INTF_MODE_CMD)
if (atomic_dec_return(&kms->bandwidth_ref) > 0)
return;
/*
* If video interface present, cmd panel bandwidth cannot be
* released.
*/
if (dpu_crtc_get_intf_mode(crtc) == INTF_MODE_CMD)
drm_for_each_crtc(tmp_crtc, crtc->dev) {
if (tmp_crtc->enabled &&
dpu_crtc_get_intf_mode(tmp_crtc) ==
INTF_MODE_VIDEO)
return;
}
/* Release the bandwidth */
if (kms->perf.enable_bw_release) {
trace_dpu_cmd_release_bw(crtc->base.id);

45
drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
View file

@ -294,19 +294,6 @@ void dpu_crtc_vblank_callback(struct drm_crtc *crtc)
trace_dpu_crtc_vblank_cb(DRMID(crtc));
}
static void dpu_crtc_release_bw_unlocked(struct drm_crtc *crtc)
{
int ret = 0;
struct drm_modeset_acquire_ctx ctx;
DRM_MODESET_LOCK_ALL_BEGIN(crtc->dev, ctx, 0, ret);
dpu_core_perf_crtc_release_bw(crtc);
DRM_MODESET_LOCK_ALL_END(ctx, ret);
if (ret)
DRM_ERROR("Failed to acquire modeset locks to release bw, %d\n",
ret);
}
static void dpu_crtc_frame_event_work(struct kthread_work *work)
{
struct dpu_crtc_frame_event *fevent = container_of(work,
@ -336,7 +323,7 @@ static void dpu_crtc_frame_event_work(struct kthread_work *work)
/* release bandwidth and other resources */
trace_dpu_crtc_frame_event_done(DRMID(crtc),
fevent->event);
dpu_crtc_release_bw_unlocked(crtc);
dpu_core_perf_crtc_release_bw(crtc);
} else {
trace_dpu_crtc_frame_event_more_pending(DRMID(crtc),
fevent->event);
@ -652,7 +639,7 @@ void dpu_crtc_commit_kickoff(struct drm_crtc *crtc, bool async)
dpu_encoder_prepare_for_kickoff(encoder, async);
if (!async) {
/* wait for frame_event_done completion */
/* 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");
@ -731,6 +718,7 @@ static void dpu_crtc_disable(struct drm_crtc *crtc,
struct drm_encoder *encoder;
struct msm_drm_private *priv;
unsigned long flags;
bool release_bandwidth = false;
if (!crtc || !crtc->dev || !crtc->dev->dev_private || !crtc->state) {
DPU_ERROR("invalid crtc\n");
@ -747,8 +735,15 @@ static void dpu_crtc_disable(struct drm_crtc *crtc,
drm_crtc_vblank_off(crtc);
drm_for_each_encoder_mask(encoder, crtc->dev,
old_crtc_state->encoder_mask)
old_crtc_state->encoder_mask) {
/* in video mode, we hold an extra bandwidth reference
* as we cannot drop bandwidth at frame-done if any
* crtc is being used in video mode.
*/
if (dpu_encoder_get_intf_mode(encoder) == INTF_MODE_VIDEO)
release_bandwidth = true;
dpu_encoder_assign_crtc(encoder, NULL);
}
/* wait for frame_event_done completion */
if (_dpu_crtc_wait_for_frame_done(crtc))
@ -762,7 +757,8 @@ static void dpu_crtc_disable(struct drm_crtc *crtc,
if (atomic_read(&dpu_crtc->frame_pending)) {
trace_dpu_crtc_disable_frame_pending(DRMID(crtc),
atomic_read(&dpu_crtc->frame_pending));
dpu_core_perf_crtc_release_bw(crtc);
if (release_bandwidth)
dpu_core_perf_crtc_release_bw(crtc);
atomic_set(&dpu_crtc->frame_pending, 0);
}
@ -794,6 +790,7 @@ static void dpu_crtc_enable(struct drm_crtc *crtc,
struct dpu_crtc *dpu_crtc;
struct drm_encoder *encoder;
struct msm_drm_private *priv;
bool request_bandwidth;
if (!crtc || !crtc->dev || !crtc->dev->dev_private) {
DPU_ERROR("invalid crtc\n");
@ -806,9 +803,19 @@ static void dpu_crtc_enable(struct drm_crtc *crtc,
DRM_DEBUG_KMS("crtc%d\n", crtc->base.id);
dpu_crtc = to_dpu_crtc(crtc);
drm_for_each_encoder_mask(encoder, crtc->dev, crtc->state->encoder_mask)
drm_for_each_encoder_mask(encoder, crtc->dev, crtc->state->encoder_mask) {
/* in video mode, we hold an extra bandwidth reference
* as we cannot drop bandwidth at frame-done if any
* crtc is being used in video mode.
*/
if (dpu_encoder_get_intf_mode(encoder) == INTF_MODE_VIDEO)
request_bandwidth = true;
dpu_encoder_register_frame_event_callback(encoder,
dpu_crtc_frame_event_cb, (void *)crtc);
}
if (request_bandwidth)
atomic_inc(&_dpu_crtc_get_kms(crtc)->bandwidth_ref);
trace_dpu_crtc_enable(DRMID(crtc), true, dpu_crtc);
dpu_crtc->enabled = true;
@ -983,6 +990,8 @@ static int dpu_crtc_atomic_check(struct drm_crtc *crtc,
}
}
atomic_inc(&_dpu_crtc_get_kms(crtc)->bandwidth_ref);
rc = dpu_core_perf_crtc_check(crtc, state);
if (rc) {
DPU_ERROR("crtc%d failed performance check %d\n",

2
drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
View file

@ -802,6 +802,8 @@ static int dpu_kms_hw_init(struct msm_kms *kms)
return rc;
}
atomic_set(&dpu_kms->bandwidth_ref, 0);
dpu_kms->mmio = msm_ioremap(dpu_kms->pdev, "mdp", "mdp");
if (IS_ERR(dpu_kms->mmio)) {
rc = PTR_ERR(dpu_kms->mmio);

8
drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
View file

@ -122,6 +122,14 @@ struct dpu_kms {
struct platform_device *pdev;
bool rpm_enabled;
struct dss_module_power mp;
/* reference count bandwidth requests, so we know when we can
* release bandwidth. Each atomic update increments, and frame-
* done event decrements. Additionally, for video mode, the
* reference is incremented when crtc is enabled, and decremented
* when disabled.
*/
atomic_t bandwidth_ref;
};
struct vsync_info {