drm/msm: block incoming update on pending updates
We can't have multiple updates pending on a given CRTC, and we don't
want a sync update to race w/ an async update that preceeded it. So
keep track of which CRTCs have updates in flight, and block later
updates that would conflict.
Signed-off-by: Rob Clark <robdclark@gmail.com>
diff --git a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_crtc.c b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_crtc.c
index a7672e1..3449213 100644
--- a/drivers/gpu/drm/msm/mdp/mdp4/mdp4_crtc.c
+++ b/drivers/gpu/drm/msm/mdp/mdp4/mdp4_crtc.c
@@ -331,17 +331,8 @@
struct drm_crtc_state *state)
{
struct mdp4_crtc *mdp4_crtc = to_mdp4_crtc(crtc);
- struct drm_device *dev = crtc->dev;
-
DBG("%s: check", mdp4_crtc->name);
-
- if (mdp4_crtc->event) {
- dev_err(dev->dev, "already pending flip!\n");
- return -EBUSY;
- }
-
// TODO anything else to check?
-
return 0;
}
@@ -357,7 +348,7 @@
struct drm_device *dev = crtc->dev;
unsigned long flags;
- DBG("%s: flush", mdp4_crtc->name);
+ DBG("%s: event: %p", mdp4_crtc->name, crtc->state->event);
WARN_ON(mdp4_crtc->event);
diff --git a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_crtc.c b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_crtc.c
index 0e9a2e3..930bcec 100644
--- a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_crtc.c
+++ b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_crtc.c
@@ -303,11 +303,6 @@
DBG("%s: check", mdp5_crtc->name);
- if (mdp5_crtc->event) {
- dev_err(dev->dev, "already pending flip!\n");
- return -EBUSY;
- }
-
/* request a free CTL, if none is already allocated for this CRTC */
if (state->enable && !mdp5_crtc->ctl) {
mdp5_crtc->ctl = mdp5_ctlm_request(mdp5_kms->ctlm, crtc);
@@ -364,7 +359,7 @@
struct drm_device *dev = crtc->dev;
unsigned long flags;
- DBG("%s: flush", mdp5_crtc->name);
+ DBG("%s: event: %p", mdp5_crtc->name, crtc->state->event);
WARN_ON(mdp5_crtc->event);
diff --git a/drivers/gpu/drm/msm/msm_atomic.c b/drivers/gpu/drm/msm/msm_atomic.c
index f0de412..1919682 100644
--- a/drivers/gpu/drm/msm/msm_atomic.c
+++ b/drivers/gpu/drm/msm/msm_atomic.c
@@ -23,10 +23,41 @@
struct drm_atomic_state *state;
uint32_t fence;
struct msm_fence_cb fence_cb;
+ uint32_t crtc_mask;
};
static void fence_cb(struct msm_fence_cb *cb);
+/* block until specified crtcs are no longer pending update, and
+ * atomically mark them as pending update
+ */
+static int start_atomic(struct msm_drm_private *priv, uint32_t crtc_mask)
+{
+ int ret;
+
+ spin_lock(&priv->pending_crtcs_event.lock);
+ ret = wait_event_interruptible_locked(priv->pending_crtcs_event,
+ !(priv->pending_crtcs & crtc_mask));
+ if (ret == 0) {
+ DBG("start: %08x", crtc_mask);
+ priv->pending_crtcs |= crtc_mask;
+ }
+ spin_unlock(&priv->pending_crtcs_event.lock);
+
+ return ret;
+}
+
+/* clear specified crtcs (no longer pending update)
+ */
+static void end_atomic(struct msm_drm_private *priv, uint32_t crtc_mask)
+{
+ spin_lock(&priv->pending_crtcs_event.lock);
+ DBG("end: %08x", crtc_mask);
+ priv->pending_crtcs &= ~crtc_mask;
+ wake_up_all_locked(&priv->pending_crtcs_event);
+ spin_unlock(&priv->pending_crtcs_event.lock);
+}
+
static struct msm_commit *new_commit(struct drm_atomic_state *state)
{
struct msm_commit *c = kzalloc(sizeof(*c), GFP_KERNEL);
@@ -58,12 +89,27 @@
drm_atomic_helper_commit_post_planes(dev, state);
+ /* NOTE: _wait_for_vblanks() only waits for vblank on
+ * enabled CRTCs. So we end up faulting when disabling
+ * due to (potentially) unref'ing the outgoing fb's
+ * before the vblank when the disable has latched.
+ *
+ * But if it did wait on disabled (or newly disabled)
+ * CRTCs, that would be racy (ie. we could have missed
+ * the irq. We need some way to poll for pipe shut
+ * down. Or just live with occasionally hitting the
+ * timeout in the CRTC disable path (which really should
+ * not be critical path)
+ */
+
drm_atomic_helper_wait_for_vblanks(dev, state);
drm_atomic_helper_cleanup_planes(dev, state);
drm_atomic_state_free(state);
+ end_atomic(dev->dev_private, c->crtc_mask);
+
kfree(c);
}
@@ -97,8 +143,9 @@
int msm_atomic_commit(struct drm_device *dev,
struct drm_atomic_state *state, bool async)
{
- struct msm_commit *c;
int nplanes = dev->mode_config.num_total_plane;
+ int ncrtcs = dev->mode_config.num_crtc;
+ struct msm_commit *c;
int i, ret;
ret = drm_atomic_helper_prepare_planes(dev, state);
@@ -106,6 +153,18 @@
return ret;
c = new_commit(state);
+ if (!c)
+ return -ENOMEM;
+
+ /*
+ * Figure out what crtcs we have:
+ */
+ for (i = 0; i < ncrtcs; i++) {
+ struct drm_crtc *crtc = state->crtcs[i];
+ if (!crtc)
+ continue;
+ c->crtc_mask |= (1 << drm_crtc_index(crtc));
+ }
/*
* Figure out what fence to wait for:
@@ -122,6 +181,14 @@
}
/*
+ * Wait for pending updates on any of the same crtc's and then
+ * mark our set of crtc's as busy:
+ */
+ ret = start_atomic(dev->dev_private, c->crtc_mask);
+ if (ret)
+ return ret;
+
+ /*
* This is the point of no return - everything below never fails except
* when the hw goes bonghits. Which means we can commit the new state on
* the software side now.
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index d3b791b..7e1c71e 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -193,6 +193,7 @@
priv->wq = alloc_ordered_workqueue("msm", 0);
init_waitqueue_head(&priv->fence_event);
+ init_waitqueue_head(&priv->pending_crtcs_event);
INIT_LIST_HEAD(&priv->inactive_list);
INIT_LIST_HEAD(&priv->fence_cbs);
diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
index 1363038..b69ef2d 100644
--- a/drivers/gpu/drm/msm/msm_drv.h
+++ b/drivers/gpu/drm/msm/msm_drv.h
@@ -96,6 +96,10 @@
/* callbacks deferred until bo is inactive: */
struct list_head fence_cbs;
+ /* crtcs pending async atomic updates: */
+ uint32_t pending_crtcs;
+ wait_queue_head_t pending_crtcs_event;
+
/* registered MMUs: */
unsigned int num_mmus;
struct msm_mmu *mmus[NUM_DOMAINS];