The atomic API can allow us to test state before we apply it, to see if
it will be valid. Use this when we construct a plane configuration, to
see if it has a chance of ever working. If not, we can fail
assign_planes early.
This will be used in later patches to incrementally build state by
proposing and testing potential configurations one at a time.
Signed-off-by: Daniel Stone <dani...@collabora.com>
Tested-by: Emre Ucan <eu...@de.adit-jv.com>
---
libweston/compositor-drm.c | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/libweston/compositor-drm.c b/libweston/compositor-drm.c
index 28a580cd2..f7a364837 100644
--- a/libweston/compositor-drm.c
+++ b/libweston/compositor-drm.c
@@ -260,6 +260,7 @@ enum drm_output_state_duplicate_mode {
enum drm_state_apply_mode {
DRM_STATE_APPLY_SYNC, /**< state fully processed */
DRM_STATE_APPLY_ASYNC, /**< state pending event delivery */
+ DRM_STATE_TEST_ONLY, /**< test if the state can be applied */
};
struct drm_backend {
@@ -1822,6 +1823,7 @@ drm_pending_state_get_output(struct drm_pending_state
*pending_state,
}
static int drm_pending_state_apply_sync(struct drm_pending_state *state);
+static int drm_pending_state_test(struct drm_pending_state *state);
/**
* Mark a drm_output_state (the output's last state) as complete. This handles
@@ -2610,9 +2612,16 @@ drm_pending_state_apply_atomic(struct drm_pending_state
*pending_state,
case DRM_STATE_APPLY_ASYNC:
flags |= DRM_MODE_PAGE_FLIP_EVENT | DRM_MODE_ATOMIC_NONBLOCK;
break;
+ case DRM_STATE_TEST_ONLY:
+ flags |= DRM_MODE_ATOMIC_TEST_ONLY;
+ break;
}
ret = drmModeAtomicCommit(b->drm.fd, req, flags, b);
+
+ if (mode == DRM_STATE_TEST_ONLY)
+ return ret;
+
if (ret != 0) {
weston_log("atomic: couldn't commit new state: %m\n");
goto out;
@@ -2640,6 +2649,22 @@ out:
*
* Unconditionally takes ownership of pending_state, and clears state_invalid.
*/
+static int
+drm_pending_state_test(struct drm_pending_state *pending_state)
+{
+#ifdef HAVE_DRM_ATOMIC
+ struct drm_backend *b = pending_state->backend;
+
+ if (b->atomic_modeset)
+ return drm_pending_state_apply_atomic(pending_state,
+ DRM_STATE_TEST_ONLY);
+#endif
+
+ /* We have no way to test state before application on the legacy
+ * modesetting API, so just claim it succeeded. */
+ return 0;
+}
+
static int
drm_pending_state_apply(struct drm_pending_state *pending_state)
{
@@ -3271,6 +3296,7 @@ drm_output_propose_state(struct weston_output
*output_base,
struct weston_view *ev;
pixman_region32_t surface_overlap, renderer_region, occluded_region;
bool planes_ok = (mode != DRM_OUTPUT_PROPOSE_STATE_RENDERER_ONLY);
+ int ret;
assert(!output->state_last);
state = drm_output_state_duplicate(output->state_cur,
@@ -3388,7 +3414,18 @@ drm_output_propose_state(struct weston_output
*output_base,
pixman_region32_fini(&renderer_region);
pixman_region32_fini(&occluded_region);
+ /* Check to see if this state will actually work. */
+ ret = drm_pending_state_test(state->pending_state);
+ if (ret != 0)
+ goto err;
+
return state;
+
+err:
+ pixman_region32_fini(&renderer_region);
+ pixman_region32_fini(&occluded_region);
+ drm_output_state_free(state);
+ return NULL;
}
static void
--
2.17.1
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