[libcamera-devel] [PATCH v3 5/5] pipeline: raspberrypi: Add notion of priority write to StaggeredCtrl
Naushir Patuck
naush at raspberrypi.com
Thu Jan 28 10:10:50 CET 2021
If an exposure time change adjusts the vblanking limits, and we write
both VBLANK and EXPOSURE controls as a set, the latter may fail if the
value is outside of the limits calculated by the old VBLANK value. This
is a limitation in V4L2 and cannot be fixed by writing VBLANK before
EXPOSURE.
The workaround here is to have the StaggeredCtrl mark the
VBLANK control as "priority write", which then write VBLANK separately
from (and ahead of) any other controls. This way, the sensor driver will
update the EXPOSURE control with new limits before the new values is
presented, and will thus be seen as valid.
In addition to this, the following changes have also been made to
the module:
- The initializer list passed into init() now uses a structure type
instead of a std::pair.
- Use unsigned int to store control delays to avoid unnecessary casts.
StaggeredCtrl is due to be deprecated and replaced by DelayedCtrl, so
this change serves more a working proof-of-concept on the workaround,
and not much care has been taken to provide a nice new API for applying
this "priority write" flag to the control. A similar workaround must be
available to DelayedCtrl eventually.
Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
---
src/ipa/raspberrypi/raspberrypi.cpp | 5 ++-
.../pipeline/raspberrypi/raspberrypi.cpp | 12 ++++--
.../pipeline/raspberrypi/staggered_ctrl.cpp | 41 +++++++++++++------
.../pipeline/raspberrypi/staggered_ctrl.h | 17 ++++++--
4 files changed, 54 insertions(+), 21 deletions(-)
diff --git a/src/ipa/raspberrypi/raspberrypi.cpp b/src/ipa/raspberrypi/raspberrypi.cpp
index 8c0e699184f6..2ad7b7dabb3e 100644
--- a/src/ipa/raspberrypi/raspberrypi.cpp
+++ b/src/ipa/raspberrypi/raspberrypi.cpp
@@ -1038,8 +1038,9 @@ void IPARPi::applyAGC(const struct AgcStatus *agcStatus, ControlList &ctrls)
/*
* Due to the behavior of V4L2, the current value of VBLANK could clip the
- * exposure time without us knowing. The next time though this function should
- * clip exposure correctly.
+ * exposure time without us knowing. We get around this by ensuring the
+ * staggered write component submits VBLANK separately from, and before the
+ * EXPOSURE control.
*/
ctrls.set(V4L2_CID_VBLANK, vblanking);
ctrls.set(V4L2_CID_EXPOSURE, exposureLines);
diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
index 524cc960dd37..2118f2e72486 100644
--- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
+++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
@@ -1229,12 +1229,18 @@ int RPiCameraData::configureIPA(const CameraConfiguration *config)
/*
* Setup our staggered control writer with the sensor default
* gain and exposure delays.
+ *
+ * VBLANK must be flagged as "priority write" to allow it to
+ * be set ahead of (and separate from) all other controls that
+ * are batched together. This is needed so that any update to the
+ * EXPOSURE control will be validated based on the new VBLANK
+ * control value.
*/
if (!staggeredCtrl_) {
staggeredCtrl_.init(unicam_[Unicam::Image].dev(),
- { { V4L2_CID_ANALOGUE_GAIN, result.data[resultIdx++] },
- { V4L2_CID_EXPOSURE, result.data[resultIdx++] },
- { V4L2_CID_VBLANK, result.data[resultIdx++] } });
+ { { V4L2_CID_ANALOGUE_GAIN, result.data[resultIdx++], false },
+ { V4L2_CID_EXPOSURE, result.data[resultIdx++], false },
+ { V4L2_CID_VBLANK, result.data[resultIdx++], true } });
sensorMetadata_ = result.data[resultIdx++];
}
}
diff --git a/src/libcamera/pipeline/raspberrypi/staggered_ctrl.cpp b/src/libcamera/pipeline/raspberrypi/staggered_ctrl.cpp
index 62605c0fceee..498cd65b4cb6 100644
--- a/src/libcamera/pipeline/raspberrypi/staggered_ctrl.cpp
+++ b/src/libcamera/pipeline/raspberrypi/staggered_ctrl.cpp
@@ -22,21 +22,23 @@ LOG_DEFINE_CATEGORY(RPI_S_W)
namespace RPi {
void StaggeredCtrl::init(V4L2VideoDevice *dev,
- std::initializer_list<std::pair<const uint32_t, uint8_t>> delayList)
+ std::initializer_list<CtrlInitParams> ctrlList)
{
std::lock_guard<std::mutex> lock(lock_);
dev_ = dev;
- delay_ = delayList;
+ ctrlParams_.clear();
ctrl_.clear();
- /* Find the largest delay across all controls. */
maxDelay_ = 0;
- for (auto const &p : delay_) {
+ for (auto const &c : ctrlList) {
LOG(RPI_S_W, Info) << "Init ctrl "
- << utils::hex(p.first) << " with delay "
- << static_cast<int>(p.second);
- maxDelay_ = std::max(maxDelay_, p.second);
+ << utils::hex(c.id) << " with delay "
+ << static_cast<int>(c.delay);
+
+ ctrlParams_[c.id] = { c.delay, c.priorityWrite };
+ /* Find the largest delay across all controls. */
+ maxDelay_ = std::max(maxDelay_, c.delay);
}
init_ = true;
@@ -67,7 +69,7 @@ bool StaggeredCtrl::set(uint32_t ctrl, int32_t value)
std::lock_guard<std::mutex> lock(lock_);
/* Can we find this ctrl as one that is registered? */
- if (delay_.find(ctrl) == delay_.end())
+ if (ctrlParams_.find(ctrl) == ctrlParams_.end())
return false;
ctrl_[ctrl][setCount_].value = value;
@@ -82,7 +84,7 @@ bool StaggeredCtrl::set(std::initializer_list<std::pair<const uint32_t, int32_t>
for (auto const &p : ctrlList) {
/* Can we find this ctrl? */
- if (delay_.find(p.first) == delay_.end())
+ if (ctrlParams_.find(p.first) == ctrlParams_.end())
return false;
ctrl_[p.first][setCount_] = CtrlInfo(p.second);
@@ -97,7 +99,7 @@ bool StaggeredCtrl::set(const ControlList &controls)
for (auto const &p : controls) {
/* Can we find this ctrl? */
- if (delay_.find(p.first) == delay_.end())
+ if (ctrlParams_.find(p.first) == ctrlParams_.end())
return false;
ctrl_[p.first][setCount_] = CtrlInfo(p.second.get<int32_t>());
@@ -117,12 +119,25 @@ int StaggeredCtrl::write()
ControlList controls(dev_->controls());
for (auto &p : ctrl_) {
- int delayDiff = maxDelay_ - delay_[p.first];
+ int delayDiff = maxDelay_ - ctrlParams_[p.first].delay;
int index = std::max<int>(0, setCount_ - delayDiff);
if (p.second[index].updated) {
- /* We need to write this value out. */
- controls.set(p.first, p.second[index].value);
+ if (ctrlParams_[p.first].priorityWrite) {
+ /*
+ * This control must be written now, it could
+ * affect validity of the other controls.
+ */
+ ControlList immediate(dev_->controls());
+ immediate.set(p.first, p.second[index].value);
+ dev_->setControls(&immediate);
+ } else {
+ /*
+ * Batch up the list of controls and write them
+ * at the end of the function.
+ */
+ controls.set(p.first, p.second[index].value);
+ }
p.second[index].updated = false;
LOG(RPI_S_W, Debug) << "Writing ctrl "
<< utils::hex(p.first) << " to "
diff --git a/src/libcamera/pipeline/raspberrypi/staggered_ctrl.h b/src/libcamera/pipeline/raspberrypi/staggered_ctrl.h
index 382fa31a6853..637629c0d9a8 100644
--- a/src/libcamera/pipeline/raspberrypi/staggered_ctrl.h
+++ b/src/libcamera/pipeline/raspberrypi/staggered_ctrl.h
@@ -23,6 +23,12 @@ namespace RPi {
class StaggeredCtrl
{
public:
+ struct CtrlInitParams {
+ unsigned int id;
+ unsigned int delay;
+ bool priorityWrite;
+ };
+
StaggeredCtrl()
: init_(false), setCount_(0), getCount_(0), maxDelay_(0)
{
@@ -34,7 +40,7 @@ public:
}
void init(V4L2VideoDevice *dev,
- std::initializer_list<std::pair<const uint32_t, uint8_t>> delayList);
+ std::initializer_list<CtrlInitParams> ctrlList);
void reset();
void get(std::unordered_map<uint32_t, int32_t> &ctrl, uint8_t offset = 0);
@@ -79,12 +85,17 @@ private:
}
};
+ struct CtrlParams {
+ unsigned int delay;
+ bool priorityWrite;
+ };
+
bool init_;
uint32_t setCount_;
uint32_t getCount_;
- uint8_t maxDelay_;
+ unsigned int maxDelay_;
V4L2VideoDevice *dev_;
- std::unordered_map<uint32_t, uint8_t> delay_;
+ std::unordered_map<uint32_t, CtrlParams> ctrlParams_;
std::unordered_map<uint32_t, CircularArray> ctrl_;
std::mutex lock_;
};
--
2.25.1
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