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backends/drm: queue cursor updates instead of replacing the original commit

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At commit time, the newest commit that's ready will be chosen, ensuring that
cursor updates added just before commit time can't delay the primary plane
update unnecessarily
This commit is contained in:
Xaver Hugl 2023-07-30 16:56:08 +02:00
parent bf17d6388c
commit 5007d337b3
3 changed files with 30 additions and 24 deletions
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44
src/backends/drm/drm_commit_thread.cpp
View file

@ -30,19 +30,20 @@ DrmCommitThread::DrmCommitThread()
return;
}
std::unique_lock lock(m_mutex);
if (!m_commit) {
if (m_commits.empty()) {
m_commitPending.wait(lock);
}
if (m_commit) {
if (!m_commits.empty()) {
const auto now = std::chrono::steady_clock::now();
if (m_targetPageflipTime > now + s_safetyMargin) {
lock.unlock();
std::this_thread::sleep_until(m_targetPageflipTime - s_safetyMargin);
lock.lock();
}
// the other thread may replace the commit, but not erase it
Q_ASSERT(m_commit);
if (!m_commit->areBuffersReadable()) {
const auto it = std::find_if(m_commits.rbegin(), m_commits.rend(), [](const auto &commit) {
return commit->areBuffersReadable();
});
if (it == m_commits.rend()) {
// reschedule, this commit would not hit the pageflip deadline anyways
if (m_vrr) {
m_targetPageflipTime += 50us;
@ -51,17 +52,23 @@ DrmCommitThread::DrmCommitThread()
}
continue;
}
const bool vrr = m_commit->isVrr();
if (m_commit->commit()) {
auto &commit = *it;
const bool vrr = commit->isVrr();
const bool success = commit->commit();
if (success) {
m_vrr = vrr;
// the atomic commit takes ownership of the object
m_commit.release();
} else {
qCWarning(KWIN_DRM) << "atomic commit failed:" << strerror(errno);
m_droppedCommits.push_back(std::move(m_commit));
QMetaObject::invokeMethod(this, &DrmCommitThread::commitFailed, Qt::ConnectionType::QueuedConnection);
QMetaObject::invokeMethod(this, &DrmCommitThread::clearDroppedCommits, Qt::ConnectionType::QueuedConnection);
commit.release();
}
for (auto &commit : m_commits) {
m_droppedCommits.push_back(std::move(commit));
}
m_commits.clear();
if (!success) {
qCWarning(KWIN_DRM) << "atomic commit failed:" << strerror(errno);
QMetaObject::invokeMethod(this, &DrmCommitThread::commitFailed, Qt::ConnectionType::QueuedConnection);
}
QMetaObject::invokeMethod(this, &DrmCommitThread::clearDroppedCommits, Qt::ConnectionType::QueuedConnection);
}
}
}));
@ -75,10 +82,10 @@ DrmCommitThread::~DrmCommitThread()
m_thread->wait();
}
void DrmCommitThread::setCommit(std::unique_ptr<DrmAtomicCommit> &&commit)
void DrmCommitThread::addCommit(std::unique_ptr<DrmAtomicCommit> &&commit)
{
std::unique_lock lock(m_mutex);
m_commit = std::move(commit);
m_commits.push_back(std::move(commit));
const auto now = std::chrono::steady_clock::now();
if (m_vrr && now >= m_lastPageflip + m_minVblankInterval) {
m_targetPageflipTime = now;
@ -88,12 +95,11 @@ void DrmCommitThread::setCommit(std::unique_ptr<DrmAtomicCommit> &&commit)
m_commitPending.notify_all();
}
bool DrmCommitThread::replaceCommit(std::unique_ptr<DrmAtomicCommit> &&commit)
bool DrmCommitThread::updateCommit(std::unique_ptr<DrmAtomicCommit> &&commit)
{
std::unique_lock lock(m_mutex);
if (m_commit) {
m_commit = std::move(commit);
m_commitPending.notify_all();
if (!m_commits.empty()) {
m_commits.push_back(std::move(commit));
return true;
} else {
return false;

6
src/backends/drm/drm_commit_thread.h
View file

@ -29,8 +29,8 @@ public:
explicit DrmCommitThread();
~DrmCommitThread();
void setCommit(std::unique_ptr<DrmAtomicCommit> &&commit);
bool replaceCommit(std::unique_ptr<DrmAtomicCommit> &&commit);
void addCommit(std::unique_ptr<DrmAtomicCommit> &&commit);
bool updateCommit(std::unique_ptr<DrmAtomicCommit> &&commit);
void setRefreshRate(uint32_t maximum);
void pageFlipped(std::chrono::nanoseconds timestamp);
@ -42,7 +42,7 @@ private:
void clearDroppedCommits();
TimePoint estimateNextVblank(TimePoint now) const;
std::unique_ptr<DrmAtomicCommit> m_commit;
std::vector<std::unique_ptr<DrmAtomicCommit>> m_commits;
std::unique_ptr<QThread> m_thread;
std::mutex m_mutex;
std::condition_variable m_commitPending;

4
src/backends/drm/drm_pipeline.cpp
View file

@ -175,7 +175,7 @@ DrmPipeline::Error DrmPipeline::commitPipelinesAtomic(const QVector<DrmPipeline
Q_ASSERT(pipelines.size() == 1);
Q_ASSERT(unusedObjects.isEmpty());
const auto pipeline = pipelines.front();
pipeline->m_commitThread->setCommit(std::move(commit));
pipeline->m_commitThread->addCommit(std::move(commit));
pipeline->atomicCommitSuccessful();
return Error::None;
}
@ -186,7 +186,7 @@ DrmPipeline::Error DrmPipeline::commitPipelinesAtomic(const QVector<DrmPipeline
return errnoToError();
}
const auto pipeline = pipelines.front();
if (pipeline->m_commitThread->replaceCommit(std::move(commit))) {
if (pipeline->m_commitThread->updateCommit(std::move(commit))) {
pipeline->atomicCommitSuccessful();
}
return Error::None;